// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "chrome/browser/extensions/chrome_content_browser_client_extensions_part.h"

#include <stddef.h>

#include <memory>
#include <set>

#include "base/command_line.h"
#include "base/debug/alias.h"
#include "base/debug/dump_without_crashing.h"
#include "base/metrics/histogram_macros.h"
#include "chrome/browser/browser_process.h"
#include "chrome/browser/extensions/extension_service.h"
#include "chrome/browser/extensions/extension_web_ui.h"
#include "chrome/browser/extensions/extension_webkit_preferences.h"
#include "chrome/browser/media_galleries/fileapi/media_file_system_backend.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/browser/profiles/profile_io_data.h"
#include "chrome/browser/profiles/profile_manager.h"
#include "chrome/browser/renderer_host/chrome_extension_message_filter.h"
#include "chrome/browser/sync_file_system/local/sync_file_system_backend.h"
#include "chrome/common/chrome_constants.h"
#include "chrome/common/chrome_switches.h"
#include "chrome/common/extensions/extension_constants.h"
#include "chrome/common/url_constants.h"
#include "components/dom_distiller/core/url_constants.h"
#include "components/guest_view/browser/guest_view_message_filter.h"
#include "content/public/browser/browser_thread.h"
#include "content/public/browser/browser_url_handler.h"
#include "content/public/browser/child_process_security_policy.h"
#include "content/public/browser/page_navigator.h"
#include "content/public/browser/render_process_host.h"
#include "content/public/browser/render_view_host.h"
#include "content/public/browser/resource_dispatcher_host.h"
#include "content/public/browser/site_instance.h"
#include "content/public/browser/storage_partition.h"
#include "content/public/browser/vpn_service_proxy.h"
#include "content/public/browser/web_contents.h"
#include "content/public/common/content_switches.h"
#include "content/public/common/url_constants.h"
#include "extensions/browser/api/web_request/web_request_api.h"
#include "extensions/browser/api/web_request/web_request_api_helpers.h"
#include "extensions/browser/bad_message.h"
#include "extensions/browser/extension_host.h"
#include "extensions/browser/extension_message_filter.h"
#include "extensions/browser/extension_registry.h"
#include "extensions/browser/extension_service_worker_message_filter.h"
#include "extensions/browser/extension_system.h"
#include "extensions/browser/guest_view/extensions_guest_view_message_filter.h"
#include "extensions/browser/guest_view/web_view/web_view_renderer_state.h"
#include "extensions/browser/info_map.h"
#include "extensions/browser/io_thread_extension_message_filter.h"
#include "extensions/browser/view_type_utils.h"
#include "extensions/common/constants.h"
#include "extensions/common/extensions_client.h"
#include "extensions/common/manifest_constants.h"
#include "extensions/common/manifest_handlers/app_isolation_info.h"
#include "extensions/common/manifest_handlers/background_info.h"
#include "extensions/common/manifest_handlers/web_accessible_resources_info.h"
#include "extensions/common/permissions/permissions_data.h"
#include "extensions/common/switches.h"
#include "url/origin.h"

#if defined(OS_CHROMEOS)
#include "extensions/browser/api/vpn_provider/vpn_service.h"
#include "extensions/browser/api/vpn_provider/vpn_service_factory.h"
#endif  // defined(OS_CHROMEOS)

using content::BrowserContext;
using content::BrowserThread;
using content::BrowserURLHandler;
using content::RenderViewHost;
using content::SiteInstance;
using content::WebContents;
using content::WebPreferences;

namespace extensions {

namespace {

// Used by the GetPrivilegeRequiredByUrl() and GetProcessPrivilege() functions
// below.  Extension, and isolated apps require different privileges to be
// granted to their RenderProcessHosts.  This classification allows us to make
// sure URLs are served by hosts with the right set of privileges.
enum RenderProcessHostPrivilege {
  PRIV_NORMAL,
  PRIV_HOSTED,
  PRIV_ISOLATED,
  PRIV_EXTENSION,
};

// Specifies the scheme of the SiteInstance responsible for a failed
// web-accessible resource check in ShouldAllowOpenURL.
//
// This enum backs an UMA histogram.  The order of existing values
// should not be changed.  Add any new values before SCHEME_LAST, and also run
// update_should_allow_open_url_histograms.py to update the corresponding enum
// in histograms.xml.  This enum must also be synchronized to kSchemeNames in
// RecordShouldAllowOpenURLFailure.
enum ShouldAllowOpenURLFailureScheme {
  SCHEME_UNKNOWN,
  SCHEME_EMPTY,
  SCHEME_HTTP,
  SCHEME_HTTPS,
  SCHEME_FILE,
  SCHEME_FTP,
  SCHEME_DATA,
  SCHEME_JAVASCRIPT,
  SCHEME_ABOUT,
  SCHEME_CHROME,
  SCHEME_DEVTOOLS,
  SCHEME_GUEST,
  SCHEME_VIEWSOURCE,
  SCHEME_CHROME_SEARCH,
  SCHEME_CHROME_NATIVE,
  SCHEME_DOM_DISTILLER,
  SCHEME_CHROME_EXTENSION,
  SCHEME_CONTENT,
  SCHEME_BLOB,
  SCHEME_FILESYSTEM,
  // Add new entries above and make sure to update histograms.xml by running
  // update_should_allow_open_url_histograms.py.
  SCHEME_LAST,
};

RenderProcessHostPrivilege GetPrivilegeRequiredByUrl(
    const GURL& url,
    ExtensionRegistry* registry) {
  // Default to a normal renderer cause it is lower privileged. This should only
  // occur if the URL on a site instance is either malformed, or uninitialized.
  // If it is malformed, then there is no need for better privileges anyways.
  // If it is uninitialized, but eventually settles on being an a scheme other
  // than normal webrenderer, the navigation logic will correct us out of band
  // anyways.
  if (!url.is_valid())
    return PRIV_NORMAL;

  if (!url.SchemeIs(kExtensionScheme))
    return PRIV_NORMAL;

  const Extension* extension =
      registry->enabled_extensions().GetByID(url.host());
  if (extension && AppIsolationInfo::HasIsolatedStorage(extension))
    return PRIV_ISOLATED;
  if (extension && extension->is_hosted_app())
    return PRIV_HOSTED;
  return PRIV_EXTENSION;
}

RenderProcessHostPrivilege GetProcessPrivilege(
    content::RenderProcessHost* process_host,
    ProcessMap* process_map,
    ExtensionRegistry* registry) {
  std::set<std::string> extension_ids =
      process_map->GetExtensionsInProcess(process_host->GetID());
  if (extension_ids.empty())
    return PRIV_NORMAL;

  for (const std::string& extension_id : extension_ids) {
    const Extension* extension =
        registry->enabled_extensions().GetByID(extension_id);
    if (extension && AppIsolationInfo::HasIsolatedStorage(extension))
      return PRIV_ISOLATED;
    if (extension && extension->is_hosted_app())
      return PRIV_HOSTED;
  }

  return PRIV_EXTENSION;
}

// Determines whether the extension |origin| is legal to use in an Origin header
// from the process identified by |child_id|.  Returns CONTINUE if so, FAIL if
// the extension is not recognized (and may recently have been uninstalled), and
// KILL if the origin is from a platform app but the request does not come from
// that app.
content::HeaderInterceptorResult CheckOriginHeader(
    content::ResourceContext* resource_context,
    int child_id,
    const GURL& origin) {
  DCHECK_CURRENTLY_ON(BrowserThread::IO);

  // Consider non-extension URLs safe; they will be checked elsewhere.
  if (!origin.SchemeIs(kExtensionScheme))
    return content::HeaderInterceptorResult::CONTINUE;

  // If there is no extension installed for the origin, it may be from a
  // recently uninstalled extension.  The tabs of such extensions are
  // automatically closed, but subframes and content scripts may stick around.
  // Fail such requests without killing the process.
  // TODO(rdevlin.cronin, creis): Track which extensions have been uninstalled
  // and use HeaderInterceptorResult::KILL for anything not on the list.
  // See https://crbug.com/705128.
  ProfileIOData* io_data = ProfileIOData::FromResourceContext(resource_context);
  InfoMap* extension_info_map = io_data->GetExtensionInfoMap();
  const Extension* extension =
      extension_info_map->extensions().GetExtensionOrAppByURL(origin);
  if (!extension)
    return content::HeaderInterceptorResult::FAIL;

  // Check for platform app origins.  These can only be committed by the app
  // itself, or by one if its guests if it has the webview permission.
  // Processes that incorrectly claim to be an app should be killed.
  const ProcessMap& process_map = extension_info_map->process_map();
  if (extension->is_platform_app() &&
      !process_map.Contains(extension->id(), child_id)) {
    // This is a platform app origin not in the app's own process.  If it cannot
    // create webviews, this is illegal.
    if (!extension->permissions_data()->HasAPIPermission(
            extensions::APIPermission::kWebView)) {
      return content::HeaderInterceptorResult::KILL;
    }

    // If there are accessible resources, the origin is only legal if the
    // given process is a guest of the app.
    std::string owner_extension_id;
    int owner_process_id;
    WebViewRendererState::GetInstance()->GetOwnerInfo(
        child_id, &owner_process_id, &owner_extension_id);
    const Extension* owner_extension =
        extension_info_map->extensions().GetByID(owner_extension_id);
    if (!owner_extension || owner_extension != extension)
      return content::HeaderInterceptorResult::KILL;

    // It's a valid guest of the app, so allow it to proceed.
    return content::HeaderInterceptorResult::CONTINUE;
  }

  // With only the origin and not the full URL, we don't have enough
  // information to validate hosted apps or web_accessible_resources in normal
  // extensions. Assume they're legal.
  return content::HeaderInterceptorResult::CONTINUE;
}

// This callback is registered on the ResourceDispatcherHost for the chrome
// extension Origin scheme. We determine whether the extension origin is
// valid. Please see the CheckOriginHeader() function.
void OnHttpHeaderReceived(const std::string& header,
                          const std::string& value,
                          int child_id,
                          content::ResourceContext* resource_context,
                          content::OnHeaderProcessedCallback callback) {
  DCHECK_CURRENTLY_ON(BrowserThread::IO);

  GURL origin(value);
  DCHECK(origin.SchemeIs(extensions::kExtensionScheme));

  callback.Run(CheckOriginHeader(resource_context, child_id, origin));
}

}  // namespace

ChromeContentBrowserClientExtensionsPart::
    ChromeContentBrowserClientExtensionsPart() {
}

ChromeContentBrowserClientExtensionsPart::
    ~ChromeContentBrowserClientExtensionsPart() {
}

// static
GURL ChromeContentBrowserClientExtensionsPart::GetEffectiveURL(
    Profile* profile,
    const GURL& url) {
  // If the input |url| is part of an installed app, the effective URL is an
  // extension URL with the ID of that extension as the host. This has the
  // effect of grouping apps together in a common SiteInstance.
  ExtensionRegistry* registry = ExtensionRegistry::Get(profile);
  if (!registry)
    return url;

  const Extension* extension =
      registry->enabled_extensions().GetHostedAppByURL(url);
  if (!extension)
    return url;

  // Bookmark apps do not use the hosted app process model, and should be
  // treated as normal URLs.
  if (extension->from_bookmark())
    return url;

  // If |url| corresponds to both an isolated origin and a hosted app,
  // determine whether to use the effective URL, which also determines whether
  // the isolated origin should take precedence over a matching hosted app:
  // - Chrome Web Store should always be resolved to its effective URL, so that
  //   the CWS process gets proper bindings.
  // - for other hosted apps, if the isolated origin covers the app's entire
  //   web extent (i.e., *all* URLs matched by the hosted app will have this
  //   isolated origin), allow the hosted app to take effect and return an
  //   effective URL.
  // - for other cases, disallow effective URLs, as otherwise this would allow
  //   the isolated origin to share the hosted app process with other origins
  //   it does not trust, due to https://crbug.com/791796.
  //
  // TODO(alexmos): Revisit and possibly remove this once
  // https://crbug.com/791796 is fixed.
  url::Origin isolated_origin;
  auto* policy = content::ChildProcessSecurityPolicy::GetInstance();
  bool is_isolated_origin = policy->GetMatchingIsolatedOrigin(
      url::Origin::Create(url), &isolated_origin);
  if (is_isolated_origin && extension->id() != kWebStoreAppId &&
      !DoesOriginMatchAllURLsInWebExtent(isolated_origin,
                                         extension->web_extent())) {
    return url;
  }

  // If the URL is part of an extension's web extent, convert it to an
  // extension URL.
  return extension->GetResourceURL(url.path());
}

// static
bool ChromeContentBrowserClientExtensionsPart::ShouldUseProcessPerSite(
    Profile* profile, const GURL& effective_url) {
  if (!effective_url.SchemeIs(kExtensionScheme))
    return false;

  ExtensionRegistry* registry = ExtensionRegistry::Get(profile);
  if (!registry)
    return false;

  const Extension* extension =
      registry->enabled_extensions().GetByID(effective_url.host());
  if (!extension)
    return false;

  // If the URL is part of a hosted app that does not have the background
  // permission, or that does not allow JavaScript access to the background
  // page, we want to give each instance its own process to improve
  // responsiveness.
  if (extension->GetType() == Manifest::TYPE_HOSTED_APP) {
    if (!extension->permissions_data()->HasAPIPermission(
            APIPermission::kBackground) ||
        !BackgroundInfo::AllowJSAccess(extension)) {
      return false;
    }
  }

  // Hosted apps that have script access to their background page must use
  // process per site, since all instances can make synchronous calls to the
  // background window.  Other extensions should use process per site as well.
  return true;
}

// static
bool ChromeContentBrowserClientExtensionsPart::DoesSiteRequireDedicatedProcess(
    content::BrowserContext* browser_context,
    const GURL& effective_site_url) {
  const Extension* extension = ExtensionRegistry::Get(browser_context)
                                   ->enabled_extensions()
                                   .GetExtensionOrAppByURL(effective_site_url);
  if (!extension)
    return false;

  // Always isolate Chrome Web Store.
  if (extension->id() == kWebStoreAppId)
    return true;

  // Extensions should be isolated, except for hosted apps. Isolating hosted
  // apps is a good idea, but ought to be a separate knob.
  if (extension->is_hosted_app())
    return false;

  // Isolate all extensions.
  return true;
}

// static
bool ChromeContentBrowserClientExtensionsPart::ShouldLockToOrigin(
    content::BrowserContext* browser_context,
    const GURL& effective_site_url) {
  // https://crbug.com/160576 workaround: Origin lock to the chrome-extension://
  // scheme for a hosted app would kill processes on legitimate requests for the
  // app's cookies.
  if (effective_site_url.SchemeIs(extensions::kExtensionScheme)) {
    const Extension* extension =
        ExtensionRegistry::Get(browser_context)
            ->enabled_extensions()
            .GetExtensionOrAppByURL(effective_site_url);
    if (extension && extension->is_hosted_app())
      return false;

    // http://crbug.com/600441 workaround: Extension process reuse, implemented
    // in ShouldTryToUseExistingProcessHost(), means that extension processes
    // aren't always actually dedicated to a single origin.
    // TODO(nick): Fix this.
    if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
            ::switches::kSitePerProcess))
      return false;
  }
  return true;
}

bool ChromeContentBrowserClientExtensionsPart::ShouldBypassDocumentBlocking(
    const url::Origin& initiator) {
  // Don't block responses for extension processes or for content scripts.
  // TODO(creis): This check can be made stricter by checking what the extension
  // has access to.
  return initiator.scheme() == extensions::kExtensionScheme;
}

// static
bool ChromeContentBrowserClientExtensionsPart::CanCommitURL(
    content::RenderProcessHost* process_host, const GURL& url) {
  DCHECK_CURRENTLY_ON(BrowserThread::UI);

  // We need to let most extension URLs commit in any process, since this can
  // be allowed due to web_accessible_resources.  Most hosted app URLs may also
  // load in any process (e.g., in an iframe).  However, the Chrome Web Store
  // cannot be loaded in iframes and should never be requested outside its
  // process.
  ExtensionRegistry* registry =
      ExtensionRegistry::Get(process_host->GetBrowserContext());
  if (!registry)
    return true;

  const Extension* new_extension =
      registry->enabled_extensions().GetExtensionOrAppByURL(url);
  if (new_extension && new_extension->is_hosted_app() &&
      new_extension->id() == kWebStoreAppId &&
      !ProcessMap::Get(process_host->GetBrowserContext())
           ->Contains(new_extension->id(), process_host->GetID())) {
    return false;
  }
  return true;
}

// static
bool ChromeContentBrowserClientExtensionsPart::IsSuitableHost(
    Profile* profile,
    content::RenderProcessHost* process_host,
    const GURL& site_url) {
  DCHECK(profile);

  ExtensionRegistry* registry = ExtensionRegistry::Get(profile);
  ProcessMap* process_map = ProcessMap::Get(profile);

  // These may be NULL during tests. In that case, just assume any site can
  // share any host.
  if (!registry || !process_map)
    return true;

  // Otherwise, just make sure the process privilege matches the privilege
  // required by the site.
  RenderProcessHostPrivilege privilege_required =
      GetPrivilegeRequiredByUrl(site_url, registry);
  return GetProcessPrivilege(process_host, process_map, registry) ==
         privilege_required;
}

// static
bool
ChromeContentBrowserClientExtensionsPart::ShouldTryToUseExistingProcessHost(
    Profile* profile, const GURL& url) {
  // This function is trying to limit the amount of processes used by extensions
  // with background pages. It uses a globally set percentage of processes to
  // run such extensions and if the limit is exceeded, it returns true, to
  // indicate to the content module to group extensions together.
  ExtensionRegistry* registry =
      profile ? ExtensionRegistry::Get(profile) : NULL;
  if (!registry)
    return false;

  // We have to have a valid extension with background page to proceed.
  const Extension* extension =
      registry->enabled_extensions().GetExtensionOrAppByURL(url);
  if (!extension)
    return false;
  if (!BackgroundInfo::HasBackgroundPage(extension))
    return false;

  std::set<int> process_ids;
  size_t max_process_count =
      content::RenderProcessHost::GetMaxRendererProcessCount();

  // Go through all profiles to ensure we have total count of extension
  // processes containing background pages, otherwise one profile can
  // starve the other.
  std::vector<Profile*> profiles = g_browser_process->profile_manager()->
      GetLoadedProfiles();
  for (size_t i = 0; i < profiles.size(); ++i) {
    ProcessManager* epm = ProcessManager::Get(profiles[i]);
    for (ExtensionHost* host : epm->background_hosts())
      process_ids.insert(host->render_process_host()->GetID());
  }

  return (process_ids.size() >
          (max_process_count * chrome::kMaxShareOfExtensionProcesses));
}

// static
bool ChromeContentBrowserClientExtensionsPart::
    ShouldSwapBrowsingInstancesForNavigation(SiteInstance* site_instance,
                                             const GURL& current_url,
                                             const GURL& new_url) {
  // If we don't have an ExtensionRegistry, then rely on the SiteInstance logic
  // in RenderFrameHostManager to decide when to swap.
  ExtensionRegistry* registry =
      ExtensionRegistry::Get(site_instance->GetBrowserContext());
  if (!registry)
    return false;

  // We must use a new BrowsingInstance (forcing a process swap and disabling
  // scripting by existing tabs) if one of the URLs corresponds to the Chrome
  // Web Store hosted app, and the other does not.
  //
  // We don't force a BrowsingInstance swap in other cases (i.e., when opening
  // a popup from one extension to a different extension, or to a non-extension
  // URL) to preserve script connections and allow use cases like postMessage
  // via window.opener. Those cases would still force a SiteInstance swap in
  // RenderFrameHostManager.  This behavior is similar to how extension
  // subframes on a web main frame are also placed in the same BrowsingInstance
  // (by the content/ part of ShouldSwapBrowsingInstancesForNavigation); this
  // check is just doing the same for top-level frames.  See
  // https://crbug.com/590068.
  const Extension* current_extension =
      registry->enabled_extensions().GetExtensionOrAppByURL(current_url);
  bool is_current_url_for_web_store =
      current_extension && current_extension->id() == kWebStoreAppId;

  const Extension* new_extension =
      registry->enabled_extensions().GetExtensionOrAppByURL(new_url);
  bool is_new_url_for_web_store =
      new_extension && new_extension->id() == kWebStoreAppId;

  // First do a process check.  We should force a BrowsingInstance swap if we
  // are going to Chrome Web Store, but the current process doesn't know about
  // CWS, even if current_extension somehow corresponds to CWS.
  ProcessMap* process_map = ProcessMap::Get(site_instance->GetBrowserContext());
  if (is_new_url_for_web_store && site_instance->HasProcess() &&
      !process_map->Contains(new_extension->id(),
                             site_instance->GetProcess()->GetID()))
    return true;

  // Otherwise, swap BrowsingInstances when transitioning to/from Chrome Web
  // Store.
  return is_current_url_for_web_store != is_new_url_for_web_store;
}

// static
bool ChromeContentBrowserClientExtensionsPart::AllowServiceWorker(
    const GURL& scope,
    const GURL& first_party_url,
    content::ResourceContext* context) {
  // We only care about extension urls.
  if (!first_party_url.SchemeIs(kExtensionScheme))
    return true;

  ProfileIOData* io_data = ProfileIOData::FromResourceContext(context);
  InfoMap* extension_info_map = io_data->GetExtensionInfoMap();
  const Extension* extension =
      extension_info_map->extensions().GetExtensionOrAppByURL(first_party_url);
  // Don't allow a service worker for an extension url with no extension (this
  // could happen in the case of, e.g., an unloaded extension).
  return extension != nullptr;
}

// static
void ChromeContentBrowserClientExtensionsPart::OverrideNavigationParams(
    content::SiteInstance* site_instance,
    ui::PageTransition* transition,
    bool* is_renderer_initiated,
    content::Referrer* referrer) {
  const Extension* extension =
      ExtensionRegistry::Get(site_instance->GetBrowserContext())
          ->enabled_extensions()
          .GetExtensionOrAppByURL(site_instance->GetSiteURL());
  if (!extension)
    return;

  if (extension->id() == extension_misc::kBookmarkManagerId &&
      ui::PageTransitionCoreTypeIs(*transition, ui::PAGE_TRANSITION_LINK)) {
    // Link clicks in the bookmark manager count as bookmarks and as browser-
    // initiated navigations.
    *transition = ui::PAGE_TRANSITION_AUTO_BOOKMARK;
    *is_renderer_initiated = false;
  }

  // Hide the referrer for extension pages. We don't want sites to see a
  // referrer of chrome-extension://<...>.
  if (extension->is_extension())
    *referrer = content::Referrer();
}

// static
bool ChromeContentBrowserClientExtensionsPart::ShouldAllowOpenURL(
    content::SiteInstance* site_instance,
    const GURL& to_url,
    bool* result) {
  DCHECK(result);

  // Using url::Origin is important to properly handle blob: and filesystem:
  // URLs.
  url::Origin to_origin = url::Origin::Create(to_url);
  if (to_origin.scheme() != kExtensionScheme) {
    // We're not responsible for protecting this resource.  Note that hosted
    // apps fall into this category.
    return false;
  }

  // Do not allow pages from the web or other extensions navigate to
  // non-web-accessible extension resources.

  ExtensionRegistry* registry =
      ExtensionRegistry::Get(site_instance->GetBrowserContext());
  const Extension* to_extension =
      registry->enabled_extensions().GetByID(to_origin.host());
  if (!to_extension) {
    // Treat non-existent extensions the same as an extension without accessible
    // resources.
    *result = false;
    return true;
  }

  GURL site_url(site_instance->GetSiteURL());
  const Extension* from_extension =
      registry->enabled_extensions().GetExtensionOrAppByURL(site_url);
  if (from_extension && from_extension == to_extension) {
    *result = true;
    return true;
  }

  // Blob and filesystem URLs are never considered web-accessible.  See
  // https://crbug.com/656752.
  if (to_url.SchemeIsFileSystem() || to_url.SchemeIsBlob()) {
    if (to_url.SchemeIsFileSystem())
      RecordShouldAllowOpenURLFailure(FAILURE_FILE_SYSTEM_URL, site_url);
    else
      RecordShouldAllowOpenURLFailure(FAILURE_BLOB_URL, site_url);

    // TODO(alexmos): Temporary instrumentation to find any regressions for
    // this blocking.  Remove after verifying that this is not breaking any
    // legitimate use cases.
    DEBUG_ALIAS_FOR_GURL(site_url_copy, site_url);
    DEBUG_ALIAS_FOR_ORIGIN(to_origin_copy, to_origin);
    base::debug::DumpWithoutCrashing();

    *result = false;
    return true;
  }

  // Navigations from chrome://, chrome-search:// and chrome-devtools:// pages
  // need to be allowed, even if |to_url| is not web-accessible. See
  // https://crbug.com/662602.
  //
  // Note that this is intentionally done after the check for blob: and
  // filesystem: URLs above, for consistency with the renderer-side checks
  // which already disallow navigations from chrome URLs to blob/filesystem
  // URLs.
  if (site_url.SchemeIs(content::kChromeUIScheme) ||
      site_url.SchemeIs(content::kChromeDevToolsScheme) ||
      site_url.SchemeIs(chrome::kChromeSearchScheme)) {
    *result = true;
    return true;
  }

  // <webview> guests should be allowed to load only webview-accessible
  // resources, but that check is done later in
  // AllowCrossRendererResourceLoadHelper, so allow <webview> guests to proceed
  // here and rely on that check instead.  See https://crbug.com/691941.
  if (site_url.SchemeIs(content::kGuestScheme)) {
    *result = true;
    return true;
  }

  if (WebAccessibleResourcesInfo::IsResourceWebAccessible(to_extension,
                                                          to_url.path())) {
    *result = true;
    return true;
  }

  if (!site_url.SchemeIsHTTPOrHTTPS() && !site_url.SchemeIs(kExtensionScheme)) {
    // This function used to incorrectly skip the web-accessible resource
    // checks in this case. Measure how often this happens.  See also
    // https://crbug.com/696034.
    RecordShouldAllowOpenURLFailure(
        FAILURE_SCHEME_NOT_HTTP_OR_HTTPS_OR_EXTENSION, site_url);
  } else {
    RecordShouldAllowOpenURLFailure(FAILURE_RESOURCE_NOT_WEB_ACCESSIBLE,
                                    site_url);
  }

  *result = false;
  return true;
}

// static
std::unique_ptr<content::VpnServiceProxy>
ChromeContentBrowserClientExtensionsPart::GetVpnServiceProxy(
    content::BrowserContext* browser_context) {
#if defined(OS_CHROMEOS)
  chromeos::VpnService* vpn_service =
      chromeos::VpnServiceFactory::GetForBrowserContext(browser_context);
  if (!vpn_service)
    return nullptr;
  return vpn_service->GetVpnServiceProxy();
#else
  return nullptr;
#endif
}

// static
bool ChromeContentBrowserClientExtensionsPart::
    ShouldFrameShareParentSiteInstanceDespiteTopDocumentIsolation(
        const GURL& subframe_url,
        content::SiteInstance* parent_site_instance) {
  const Extension* extension =
      ExtensionRegistry::Get(parent_site_instance->GetBrowserContext())
          ->enabled_extensions()
          .GetExtensionOrAppByURL(parent_site_instance->GetSiteURL());

  return extension && extension->is_hosted_app();
}

// static
void ChromeContentBrowserClientExtensionsPart::RecordShouldAllowOpenURLFailure(
    ShouldAllowOpenURLFailureReason reason,
    const GURL& site_url) {
  UMA_HISTOGRAM_ENUMERATION("Extensions.ShouldAllowOpenURL.Failure", reason,
                            FAILURE_LAST);

  // Must be kept in sync with the ShouldAllowOpenURLFailureScheme enum.
  static const char* const kSchemeNames[] = {
      "unknown",
      "",
      url::kHttpScheme,
      url::kHttpsScheme,
      url::kFileScheme,
      url::kFtpScheme,
      url::kDataScheme,
      url::kJavaScriptScheme,
      url::kAboutScheme,
      content::kChromeUIScheme,
      content::kChromeDevToolsScheme,
      content::kGuestScheme,
      content::kViewSourceScheme,
      chrome::kChromeSearchScheme,
      chrome::kChromeNativeScheme,
      dom_distiller::kDomDistillerScheme,
      extensions::kExtensionScheme,
      url::kContentScheme,
      url::kBlobScheme,
      url::kFileSystemScheme,
      "last",
  };

  static_assert(arraysize(kSchemeNames) == SCHEME_LAST + 1,
                "kSchemeNames should have SCHEME_LAST + 1 elements");

  ShouldAllowOpenURLFailureScheme scheme = SCHEME_UNKNOWN;
  for (int i = 1; i < SCHEME_LAST; i++) {
    if (site_url.SchemeIs(kSchemeNames[i])) {
      scheme = static_cast<ShouldAllowOpenURLFailureScheme>(i);
      break;
    }
  }

  UMA_HISTOGRAM_ENUMERATION("Extensions.ShouldAllowOpenURL.Failure.Scheme",
                            scheme, SCHEME_LAST);
}

// static
bool ChromeContentBrowserClientExtensionsPart::
    DoesOriginMatchAllURLsInWebExtent(const url::Origin& origin,
                                      const URLPatternSet& web_extent) {
  // This function assumes |origin| is an isolated origin, which can only have
  // an HTTP or HTTPS scheme (see IsolatedOriginUtil::IsValidIsolatedOrigin()),
  // so these are the only schemes allowed to be matched below.
  DCHECK(origin.scheme() == url::kHttpsScheme ||
         origin.scheme() == url::kHttpScheme);
  URLPattern origin_pattern(URLPattern::SCHEME_HTTPS | URLPattern::SCHEME_HTTP);
  // TODO(alexmos): Temporarily disable precise scheme matching on
  // |origin_pattern| to allow apps that use *://foo.com/ in their web extent
  // to still work with isolated origins.  See https://crbug.com/799638.  We
  // should use SetScheme(origin.scheme()) here once https://crbug.com/791796
  // is fixed.
  origin_pattern.SetScheme("*");
  origin_pattern.SetHost(origin.host());
  origin_pattern.SetPath("/*");
  // We allow matching subdomains here because |origin| is the precise origin
  // retrieved from site isolation policy. Thus, we'll only allow an extent of
  // foo.example.com and bar.example.com if the isolated origin was
  // example.com; if the isolated origin is foo.example.com, this will
  // correctly fail.
  origin_pattern.SetMatchSubdomains(true);

  URLPatternSet origin_pattern_list;
  origin_pattern_list.AddPattern(origin_pattern);
  return origin_pattern_list.Contains(web_extent);
}

void ChromeContentBrowserClientExtensionsPart::RenderProcessWillLaunch(
    content::RenderProcessHost* host) {
  int id = host->GetID();
  Profile* profile = Profile::FromBrowserContext(host->GetBrowserContext());

  host->AddFilter(new ChromeExtensionMessageFilter(id, profile));
  host->AddFilter(new ExtensionMessageFilter(id, profile));
  host->AddFilter(new IOThreadExtensionMessageFilter(id, profile));
  host->AddFilter(new ExtensionsGuestViewMessageFilter(id, profile));
  if (extensions::ExtensionsClient::Get()
          ->ExtensionAPIEnabledInExtensionServiceWorkers()) {
    host->AddFilter(new ExtensionServiceWorkerMessageFilter(
        id, profile, host->GetStoragePartition()->GetServiceWorkerContext()));
  }
}

void ChromeContentBrowserClientExtensionsPart::SiteInstanceGotProcess(
    SiteInstance* site_instance) {
  BrowserContext* context = site_instance->GetProcess()->GetBrowserContext();
  ExtensionRegistry* registry = ExtensionRegistry::Get(context);
  if (!registry)
    return;

  // Only add the process to the map if the SiteInstance's site URL is already
  // a chrome-extension:// URL. This includes hosted apps, except in rare cases
  // that a URL in the hosted app's extent is not treated as a hosted app (e.g.,
  // for isolated origins or cross-site iframes). For that case, don't look up
  // the hosted app's Extension from the site URL using GetExtensionOrAppByURL,
  // since it isn't treated as a hosted app.
  if (!site_instance->GetSiteURL().SchemeIs(kExtensionScheme))
    return;
  const Extension* extension = registry->enabled_extensions().GetByID(
      site_instance->GetSiteURL().host());
  if (!extension)
    return;

  ProcessMap::Get(context)->Insert(extension->id(),
                                   site_instance->GetProcess()->GetID(),
                                   site_instance->GetId());

  BrowserThread::PostTask(
      BrowserThread::IO, FROM_HERE,
      base::BindOnce(&InfoMap::RegisterExtensionProcess,
                     ExtensionSystem::Get(context)->info_map(), extension->id(),
                     site_instance->GetProcess()->GetID(),
                     site_instance->GetId()));
}

void ChromeContentBrowserClientExtensionsPart::SiteInstanceDeleting(
    SiteInstance* site_instance) {
  BrowserContext* context = site_instance->GetBrowserContext();
  ExtensionRegistry* registry = ExtensionRegistry::Get(context);
  if (!registry)
    return;

  const Extension* extension =
      registry->enabled_extensions().GetExtensionOrAppByURL(
          site_instance->GetSiteURL());
  if (!extension)
    return;

  ProcessMap::Get(context)->Remove(extension->id(),
                                   site_instance->GetProcess()->GetID(),
                                   site_instance->GetId());

  BrowserThread::PostTask(
      BrowserThread::IO, FROM_HERE,
      base::BindOnce(&InfoMap::UnregisterExtensionProcess,
                     ExtensionSystem::Get(context)->info_map(), extension->id(),
                     site_instance->GetProcess()->GetID(),
                     site_instance->GetId()));
}

void ChromeContentBrowserClientExtensionsPart::OverrideWebkitPrefs(
    RenderViewHost* rvh,
    WebPreferences* web_prefs) {
  const ExtensionRegistry* registry =
      ExtensionRegistry::Get(rvh->GetProcess()->GetBrowserContext());
  if (!registry)
    return;

  // Note: it's not possible for kExtensionsScheme to change during the lifetime
  // of the process.
  //
  // Ensure that we are only granting extension preferences to URLs with
  // the correct scheme. Without this check, chrome-guest:// schemes used by
  // webview tags as well as hosts that happen to match the id of an
  // installed extension would get the wrong preferences.
  const GURL& site_url = rvh->GetSiteInstance()->GetSiteURL();
  if (!site_url.SchemeIs(kExtensionScheme))
    return;

  WebContents* web_contents = WebContents::FromRenderViewHost(rvh);
  ViewType view_type = GetViewType(web_contents);
  const Extension* extension =
      registry->enabled_extensions().GetByID(site_url.host());
  extension_webkit_preferences::SetPreferences(extension, view_type, web_prefs);
}

void ChromeContentBrowserClientExtensionsPart::BrowserURLHandlerCreated(
    BrowserURLHandler* handler) {
  handler->AddHandlerPair(&ExtensionWebUI::HandleChromeURLOverride,
                          BrowserURLHandler::null_handler());
  handler->AddHandlerPair(BrowserURLHandler::null_handler(),
                          &ExtensionWebUI::HandleChromeURLOverrideReverse);
}

void ChromeContentBrowserClientExtensionsPart::
    GetAdditionalAllowedSchemesForFileSystem(
        std::vector<std::string>* additional_allowed_schemes) {
  additional_allowed_schemes->push_back(kExtensionScheme);
}

void ChromeContentBrowserClientExtensionsPart::GetURLRequestAutoMountHandlers(
    std::vector<storage::URLRequestAutoMountHandler>* handlers) {
  handlers->push_back(
      base::Bind(MediaFileSystemBackend::AttemptAutoMountForURLRequest));
}

void ChromeContentBrowserClientExtensionsPart::GetAdditionalFileSystemBackends(
    content::BrowserContext* browser_context,
    const base::FilePath& storage_partition_path,
    std::vector<std::unique_ptr<storage::FileSystemBackend>>*
        additional_backends) {
  additional_backends->push_back(
      std::make_unique<MediaFileSystemBackend>(storage_partition_path));

  additional_backends->push_back(
      std::make_unique<sync_file_system::SyncFileSystemBackend>(
          Profile::FromBrowserContext(browser_context)));
}

void ChromeContentBrowserClientExtensionsPart::
    AppendExtraRendererCommandLineSwitches(base::CommandLine* command_line,
                                           content::RenderProcessHost* process,
                                           Profile* profile) {
  if (!process)
    return;
  DCHECK(profile);
  if (ProcessMap::Get(profile)->Contains(process->GetID())) {
    command_line->AppendSwitch(switches::kExtensionProcess);
  }
}

void ChromeContentBrowserClientExtensionsPart::ResourceDispatcherHostCreated() {
  content::ResourceDispatcherHost::Get()->RegisterInterceptor(
      "Origin", kExtensionScheme, base::Bind(&OnHttpHeaderReceived));
}

}  // namespace extensions