content/browser/frame_host/frame_tree.cc - chromium/src - Git at Google

 // Copyright 2013 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 "content/browser/frame_host/frame_tree.h"

 #include <queue>

 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/containers/hash_tables.h"
 #include "base/lazy_instance.h"
 #include "content/browser/frame_host/frame_tree_node.h"
 #include "content/browser/frame_host/navigator.h"
 #include "content/browser/frame_host/render_frame_host_factory.h"
 #include "content/browser/frame_host/render_frame_host_impl.h"
 #include "content/browser/frame_host/render_frame_proxy_host.h"
 #include "content/browser/renderer_host/render_view_host_factory.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"

 namespace content {

 namespace {

 // Used with FrameTree::ForEach() to search for the FrameTreeNode
 // corresponding to |frame_tree_node_id| within a specific FrameTree.
 bool FrameTreeNodeForId(int frame_tree_node_id,
                         FrameTreeNode** out_node,
                         FrameTreeNode* node) {
   if (node->frame_tree_node_id() == frame_tree_node_id) {
     *out_node = node;
     // Terminate iteration once the node has been found.
     return false;
   }
   return true;
 }

 // Used with FrameTree::ForEach() to search for the FrameTreeNode with the given
 // |name| within a specific FrameTree.
 bool FrameTreeNodeForName(const std::string& name,
                           FrameTreeNode** out_node,
                           FrameTreeNode* node) {
   if (node->frame_name() == name) {
     *out_node = node;
     // Terminate iteration once the node has been found.
     return false;
   }
   return true;
 }

 bool CreateProxyForSiteInstance(const scoped_refptr<SiteInstance>& instance,
                                 FrameTreeNode* node) {
   // If a new frame is created in the current SiteInstance, other frames in
   // that SiteInstance don't need a proxy for the new frame.
   SiteInstance* current_instance =
       node->render_manager()->current_frame_host()->GetSiteInstance();
   if (current_instance != instance.get())
     node->render_manager()->CreateRenderFrameProxy(instance.get());
   return true;
 }

 // Helper function used with FrameTree::ForEach() for retrieving the total
 // loading progress and number of frames in a frame tree.
 bool CollectLoadProgress(double* progress,
                          int* frame_count,
                          FrameTreeNode* node) {
   // Ignore the current frame if it has not started loading.
   if (!node->has_started_loading())
     return true;

   // Collect progress.
   *progress += node->loading_progress();
   (*frame_count)++;
   return true;
 }

 // Helper function used with FrameTree::ForEach() to reset the load progress.
 bool ResetNodeLoadProgress(FrameTreeNode* node) {
   node->reset_loading_progress();
   return true;
 }

 // Helper function used with FrameTree::ForEach() to check if at least one of
 // the nodes is loading.
 bool IsNodeLoading(bool* is_loading, FrameTreeNode* node) {
   if (node->IsLoading()) {
     // There is at least one node loading, so abort traversal.
     *is_loading = true;
     return false;
   }
   return true;
 }

 }  // namespace

 FrameTree::FrameTree(Navigator* navigator,
                      RenderFrameHostDelegate* render_frame_delegate,
                      RenderViewHostDelegate* render_view_delegate,
                      RenderWidgetHostDelegate* render_widget_delegate,
                      RenderFrameHostManager::Delegate* manager_delegate)
     : render_frame_delegate_(render_frame_delegate),
       render_view_delegate_(render_view_delegate),
       render_widget_delegate_(render_widget_delegate),
       manager_delegate_(manager_delegate),
       root_(new FrameTreeNode(this,
                               navigator,
                               render_frame_delegate,
                               render_view_delegate,
                               render_widget_delegate,
                               manager_delegate,
                               // The top-level frame must always be in a
                               // document scope.
                               blink::WebTreeScopeType::Document,
                               std::string(),
                               SandboxFlags::NONE)),
       focused_frame_tree_node_id_(-1),
       load_progress_(0.0) {
 }

 FrameTree::~FrameTree() {
 }

 FrameTreeNode* FrameTree::FindByID(int frame_tree_node_id) {
   FrameTreeNode* node = nullptr;
   ForEach(base::Bind(&FrameTreeNodeForId, frame_tree_node_id, &node));
   return node;
 }

 FrameTreeNode* FrameTree::FindByRoutingID(int process_id, int routing_id) {
   RenderFrameHostImpl* render_frame_host =
       RenderFrameHostImpl::FromID(process_id, routing_id);
   if (render_frame_host) {
     FrameTreeNode* result = render_frame_host->frame_tree_node();
     if (this == result->frame_tree())
       return result;
   }

   RenderFrameProxyHost* render_frame_proxy_host =
       RenderFrameProxyHost::FromID(process_id, routing_id);
   if (render_frame_proxy_host) {
     FrameTreeNode* result = render_frame_proxy_host->frame_tree_node();
     if (this == result->frame_tree())
       return result;
   }

   return nullptr;
 }

 FrameTreeNode* FrameTree::FindByName(const std::string& name) {
   if (name.empty())
     return root_.get();

   FrameTreeNode* node = nullptr;
   ForEach(base::Bind(&FrameTreeNodeForName, name, &node));
   return node;
 }

 void FrameTree::ForEach(
     const base::Callback<bool(FrameTreeNode*)>& on_node) const {
   ForEach(on_node, nullptr);
 }

 void FrameTree::ForEach(
     const base::Callback<bool(FrameTreeNode*)>& on_node,
     FrameTreeNode* skip_this_subtree) const {
   std::queue<FrameTreeNode*> queue;
   queue.push(root_.get());

   while (!queue.empty()) {
     FrameTreeNode* node = queue.front();
     queue.pop();
     if (skip_this_subtree == node)
       continue;

     if (!on_node.Run(node))
       break;

     for (size_t i = 0; i < node->child_count(); ++i)
       queue.push(node->child_at(i));
   }
 }

 RenderFrameHostImpl* FrameTree::AddFrame(FrameTreeNode* parent,
                                          int process_id,
                                          int new_routing_id,
                                          blink::WebTreeScopeType scope,
                                          const std::string& frame_name,
                                          SandboxFlags sandbox_flags) {
   // A child frame always starts with an initial empty document, which means
   // it is in the same SiteInstance as the parent frame. Ensure that the process
   // which requested a child frame to be added is the same as the process of the
   // parent node.
   // We return nullptr if this is not the case, which can happen in a race if an
   // old RFH sends a CreateChildFrame message as we're swapping to a new RFH.
   if (parent->current_frame_host()->GetProcess()->GetID() != process_id)
     return nullptr;

   scoped_ptr<FrameTreeNode> node(
       new FrameTreeNode(this, parent->navigator(), render_frame_delegate_,
                         render_view_delegate_, render_widget_delegate_,
                         manager_delegate_, scope, frame_name, sandbox_flags));
   FrameTreeNode* node_ptr = node.get();
   // AddChild is what creates the RenderFrameHost.
   parent->AddChild(node.Pass(), process_id, new_routing_id);
   return node_ptr->current_frame_host();
 }

 void FrameTree::RemoveFrame(FrameTreeNode* child) {
   FrameTreeNode* parent = child->parent();
   if (!parent) {
     NOTREACHED() << "Unexpected RemoveFrame call for main frame.";
     return;
   }

   parent->RemoveChild(child);
 }

 void FrameTree::CreateProxiesForSiteInstance(
     FrameTreeNode* source,
     SiteInstance* site_instance) {
   // Create the swapped out RVH for the new SiteInstance. This will create
   // a top-level swapped out RFH as well, which will then be wrapped by a
   // RenderFrameProxyHost.
   if (!source->IsMainFrame()) {
     RenderViewHostImpl* render_view_host =
         source->frame_tree()->GetRenderViewHost(site_instance);
     if (!render_view_host) {
       root()->render_manager()->CreateRenderFrame(
           site_instance, nullptr, MSG_ROUTING_NONE,
           CREATE_RF_SWAPPED_OUT | CREATE_RF_HIDDEN, nullptr);
     } else {
       root()->render_manager()->EnsureRenderViewInitialized(
           source, render_view_host, site_instance);
     }
   }

   scoped_refptr<SiteInstance> instance(site_instance);

   // Proxies are created in the FrameTree in response to a node navigating to a
   // new SiteInstance. Since |source|'s navigation will replace the currently
   // loaded document, the entire subtree under |source| will be removed.
   ForEach(base::Bind(&CreateProxyForSiteInstance, instance), source);
 }

 RenderFrameHostImpl* FrameTree::GetMainFrame() const {
   return root_->current_frame_host();
 }

 FrameTreeNode* FrameTree::GetFocusedFrame() {
   return FindByID(focused_frame_tree_node_id_);
 }

 void FrameTree::SetFocusedFrame(FrameTreeNode* node) {
   focused_frame_tree_node_id_ = node->frame_tree_node_id();
 }

 void FrameTree::SetFrameRemoveListener(
     const base::Callback<void(RenderFrameHost*)>& on_frame_removed) {
   on_frame_removed_ = on_frame_removed;
 }

 RenderViewHostImpl* FrameTree::CreateRenderViewHost(SiteInstance* site_instance,
                                                     int routing_id,
                                                     int main_frame_routing_id,
                                                     bool swapped_out,
                                                     bool hidden) {
   DCHECK(main_frame_routing_id != MSG_ROUTING_NONE);
   RenderViewHostMap::iterator iter =
       render_view_host_map_.find(site_instance->GetId());
   if (iter != render_view_host_map_.end()) {
     // If a RenderViewHost's main frame is pending deletion for this
     // |site_instance|, put it in the map of RenderViewHosts pending shutdown.
     // Otherwise return the existing RenderViewHost for the SiteInstance.
     RenderFrameHostImpl* main_frame = static_cast<RenderFrameHostImpl*>(
         iter->second->GetMainFrame());
     if (main_frame->frame_tree_node()->render_manager()->IsPendingDeletion(
             main_frame)) {
       render_view_host_pending_shutdown_map_.insert(
           std::pair<int, RenderViewHostImpl*>(site_instance->GetId(),
                                               iter->second));
       render_view_host_map_.erase(iter);
     } else {
       return iter->second;
     }
   }
   RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
       RenderViewHostFactory::Create(site_instance,
                                     render_view_delegate_,
                                     render_widget_delegate_,
                                     routing_id,
                                     main_frame_routing_id,
                                     swapped_out,
                                     hidden));

   render_view_host_map_[site_instance->GetId()] = rvh;
   return rvh;
 }

 RenderViewHostImpl* FrameTree::GetRenderViewHost(SiteInstance* site_instance) {
   RenderViewHostMap::iterator iter =
       render_view_host_map_.find(site_instance->GetId());
   if (iter == render_view_host_map_.end())
     return nullptr;
   return iter->second;
 }

 void FrameTree::AddRenderViewHostRef(RenderViewHostImpl* render_view_host) {
   SiteInstance* site_instance = render_view_host->GetSiteInstance();
   RenderViewHostMap::iterator iter =
       render_view_host_map_.find(site_instance->GetId());
   CHECK(iter != render_view_host_map_.end());
   CHECK(iter->second == render_view_host);

   iter->second->increment_ref_count();
 }

 void FrameTree::ReleaseRenderViewHostRef(RenderViewHostImpl* render_view_host) {
   SiteInstance* site_instance = render_view_host->GetSiteInstance();
   int32 site_instance_id = site_instance->GetId();
   RenderViewHostMap::iterator iter =
       render_view_host_map_.find(site_instance_id);
   if (iter != render_view_host_map_.end() && iter->second == render_view_host) {
     // Decrement the refcount and shutdown the RenderViewHost if no one else is
     // using it.
     CHECK_GT(iter->second->ref_count(), 0);
     iter->second->decrement_ref_count();
     if (iter->second->ref_count() == 0) {
       iter->second->Shutdown();
       render_view_host_map_.erase(iter);
     }
   } else {
     // The RenderViewHost should be in the list of RenderViewHosts pending
     // shutdown.
     bool render_view_host_found = false;
     std::pair<RenderViewHostMultiMap::iterator,
               RenderViewHostMultiMap::iterator> result =
         render_view_host_pending_shutdown_map_.equal_range(site_instance_id);
     for (RenderViewHostMultiMap::iterator multi_iter = result.first;
          multi_iter != result.second;
          ++multi_iter) {
       if (multi_iter->second != render_view_host)
         continue;
       render_view_host_found = true;
       // Decrement the refcount and shutdown the RenderViewHost if no one else
       // is using it.
       CHECK_GT(render_view_host->ref_count(), 0);
       render_view_host->decrement_ref_count();
       if (render_view_host->ref_count() == 0) {
         render_view_host->Shutdown();
         render_view_host_pending_shutdown_map_.erase(multi_iter);
       }
       break;
     }
     CHECK(render_view_host_found);
   }
 }

 void FrameTree::FrameRemoved(FrameTreeNode* frame) {
   if (frame->frame_tree_node_id() == focused_frame_tree_node_id_)
     focused_frame_tree_node_id_ = -1;

   // No notification for the root frame.
   if (!frame->parent()) {
     CHECK_EQ(frame, root_.get());
     return;
   }

   // Notify observers of the frame removal.
   if (!on_frame_removed_.is_null())
     on_frame_removed_.Run(frame->current_frame_host());
 }

 void FrameTree::UpdateLoadProgress() {
   double progress = 0.0;
   int frame_count = 0;

   ForEach(base::Bind(&CollectLoadProgress, &progress, &frame_count));
   if (frame_count != 0)
     progress /= frame_count;

   if (progress <= load_progress_)
     return;
   load_progress_ = progress;

   // Notify the WebContents.
   root_->navigator()->GetDelegate()->DidChangeLoadProgress();
 }

 void FrameTree::ResetLoadProgress() {
   ForEach(base::Bind(&ResetNodeLoadProgress));
   load_progress_ = 0.0;
 }

 bool FrameTree::IsLoading() {
   bool is_loading = false;
   ForEach(base::Bind(&IsNodeLoading, &is_loading));
   return is_loading;
 }

 }  // namespace content
	// Copyright 2013 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 "content/browser/frame_host/frame_tree.h"

	#include <queue>

	#include "base/bind.h"
	#include "base/callback.h"
	#include "base/containers/hash_tables.h"
	#include "base/lazy_instance.h"
	#include "content/browser/frame_host/frame_tree_node.h"
	#include "content/browser/frame_host/navigator.h"
	#include "content/browser/frame_host/render_frame_host_factory.h"
	#include "content/browser/frame_host/render_frame_host_impl.h"
	#include "content/browser/frame_host/render_frame_proxy_host.h"
	#include "content/browser/renderer_host/render_view_host_factory.h"
	#include "content/browser/renderer_host/render_view_host_impl.h"

	namespace content {

	namespace {

	// Used with FrameTree::ForEach() to search for the FrameTreeNode
	// corresponding to \|frame_tree_node_id\| within a specific FrameTree.
	bool FrameTreeNodeForId(int frame_tree_node_id,
	FrameTreeNode** out_node,
	FrameTreeNode* node) {
	if (node->frame_tree_node_id() == frame_tree_node_id) {
	*out_node = node;
	// Terminate iteration once the node has been found.
	return false;
	}
	return true;
	}

	// Used with FrameTree::ForEach() to search for the FrameTreeNode with the given
	// \|name\| within a specific FrameTree.
	bool FrameTreeNodeForName(const std::string& name,
	FrameTreeNode** out_node,
	FrameTreeNode* node) {
	if (node->frame_name() == name) {
	*out_node = node;
	// Terminate iteration once the node has been found.
	return false;
	}
	return true;
	}

	bool CreateProxyForSiteInstance(const scoped_refptr<SiteInstance>& instance,
	FrameTreeNode* node) {
	// If a new frame is created in the current SiteInstance, other frames in
	// that SiteInstance don't need a proxy for the new frame.
	SiteInstance* current_instance =
	node->render_manager()->current_frame_host()->GetSiteInstance();
	if (current_instance != instance.get())
	node->render_manager()->CreateRenderFrameProxy(instance.get());
	return true;
	}

	// Helper function used with FrameTree::ForEach() for retrieving the total
	// loading progress and number of frames in a frame tree.
	bool CollectLoadProgress(double* progress,
	int* frame_count,
	FrameTreeNode* node) {
	// Ignore the current frame if it has not started loading.
	if (!node->has_started_loading())
	return true;

	// Collect progress.
	*progress += node->loading_progress();
	(*frame_count)++;
	return true;
	}

	// Helper function used with FrameTree::ForEach() to reset the load progress.
	bool ResetNodeLoadProgress(FrameTreeNode* node) {
	node->reset_loading_progress();
	return true;
	}

	// Helper function used with FrameTree::ForEach() to check if at least one of
	// the nodes is loading.
	bool IsNodeLoading(bool* is_loading, FrameTreeNode* node) {
	if (node->IsLoading()) {
	// There is at least one node loading, so abort traversal.
	*is_loading = true;
	return false;
	}
	return true;
	}

	} // namespace

	FrameTree::FrameTree(Navigator* navigator,
	RenderFrameHostDelegate* render_frame_delegate,
	RenderViewHostDelegate* render_view_delegate,
	RenderWidgetHostDelegate* render_widget_delegate,
	RenderFrameHostManager::Delegate* manager_delegate)
	: render_frame_delegate_(render_frame_delegate),
	render_view_delegate_(render_view_delegate),
	render_widget_delegate_(render_widget_delegate),
	manager_delegate_(manager_delegate),
	root_(new FrameTreeNode(this,
	navigator,
	render_frame_delegate,
	render_view_delegate,
	render_widget_delegate,
	manager_delegate,
	// The top-level frame must always be in a
	// document scope.
	blink::WebTreeScopeType::Document,
	std::string(),
	SandboxFlags::NONE)),
	focused_frame_tree_node_id_(-1),
	load_progress_(0.0) {
	}

	FrameTree::~FrameTree() {
	}

	FrameTreeNode* FrameTree::FindByID(int frame_tree_node_id) {
	FrameTreeNode* node = nullptr;
	ForEach(base::Bind(&FrameTreeNodeForId, frame_tree_node_id, &node));
	return node;
	}

	FrameTreeNode* FrameTree::FindByRoutingID(int process_id, int routing_id) {
	RenderFrameHostImpl* render_frame_host =
	RenderFrameHostImpl::FromID(process_id, routing_id);
	if (render_frame_host) {
	FrameTreeNode* result = render_frame_host->frame_tree_node();
	if (this == result->frame_tree())
	return result;
	}

	RenderFrameProxyHost* render_frame_proxy_host =
	RenderFrameProxyHost::FromID(process_id, routing_id);
	if (render_frame_proxy_host) {
	FrameTreeNode* result = render_frame_proxy_host->frame_tree_node();
	if (this == result->frame_tree())
	return result;
	}

	return nullptr;
	}

	FrameTreeNode* FrameTree::FindByName(const std::string& name) {
	if (name.empty())
	return root_.get();

	FrameTreeNode* node = nullptr;
	ForEach(base::Bind(&FrameTreeNodeForName, name, &node));
	return node;
	}

	void FrameTree::ForEach(
	const base::Callback<bool(FrameTreeNode*)>& on_node) const {
	ForEach(on_node, nullptr);
	}

	void FrameTree::ForEach(
	const base::Callback<bool(FrameTreeNode*)>& on_node,
	FrameTreeNode* skip_this_subtree) const {
	std::queue<FrameTreeNode*> queue;
	queue.push(root_.get());

	while (!queue.empty()) {
	FrameTreeNode* node = queue.front();
	queue.pop();
	if (skip_this_subtree == node)
	continue;

	if (!on_node.Run(node))
	break;

	for (size_t i = 0; i < node->child_count(); ++i)
	queue.push(node->child_at(i));
	}
	}

	RenderFrameHostImpl* FrameTree::AddFrame(FrameTreeNode* parent,
	int process_id,
	int new_routing_id,
	blink::WebTreeScopeType scope,
	const std::string& frame_name,
	SandboxFlags sandbox_flags) {
	// A child frame always starts with an initial empty document, which means
	// it is in the same SiteInstance as the parent frame. Ensure that the process
	// which requested a child frame to be added is the same as the process of the
	// parent node.
	// We return nullptr if this is not the case, which can happen in a race if an
	// old RFH sends a CreateChildFrame message as we're swapping to a new RFH.
	if (parent->current_frame_host()->GetProcess()->GetID() != process_id)
	return nullptr;

	scoped_ptr<FrameTreeNode> node(
	new FrameTreeNode(this, parent->navigator(), render_frame_delegate_,
	render_view_delegate_, render_widget_delegate_,
	manager_delegate_, scope, frame_name, sandbox_flags));
	FrameTreeNode* node_ptr = node.get();
	// AddChild is what creates the RenderFrameHost.
	parent->AddChild(node.Pass(), process_id, new_routing_id);
	return node_ptr->current_frame_host();
	}

	void FrameTree::RemoveFrame(FrameTreeNode* child) {
	FrameTreeNode* parent = child->parent();
	if (!parent) {
	NOTREACHED() << "Unexpected RemoveFrame call for main frame.";
	return;
	}

	parent->RemoveChild(child);
	}

	void FrameTree::CreateProxiesForSiteInstance(
	FrameTreeNode* source,
	SiteInstance* site_instance) {
	// Create the swapped out RVH for the new SiteInstance. This will create
	// a top-level swapped out RFH as well, which will then be wrapped by a
	// RenderFrameProxyHost.
	if (!source->IsMainFrame()) {
	RenderViewHostImpl* render_view_host =
	source->frame_tree()->GetRenderViewHost(site_instance);
	if (!render_view_host) {
	root()->render_manager()->CreateRenderFrame(
	site_instance, nullptr, MSG_ROUTING_NONE,
	CREATE_RF_SWAPPED_OUT \| CREATE_RF_HIDDEN, nullptr);
	} else {
	root()->render_manager()->EnsureRenderViewInitialized(
	source, render_view_host, site_instance);
	}
	}

	scoped_refptr<SiteInstance> instance(site_instance);

	// Proxies are created in the FrameTree in response to a node navigating to a
	// new SiteInstance. Since \|source\|'s navigation will replace the currently
	// loaded document, the entire subtree under \|source\| will be removed.
	ForEach(base::Bind(&CreateProxyForSiteInstance, instance), source);
	}

	RenderFrameHostImpl* FrameTree::GetMainFrame() const {
	return root_->current_frame_host();
	}

	FrameTreeNode* FrameTree::GetFocusedFrame() {
	return FindByID(focused_frame_tree_node_id_);
	}

	void FrameTree::SetFocusedFrame(FrameTreeNode* node) {
	focused_frame_tree_node_id_ = node->frame_tree_node_id();
	}

	void FrameTree::SetFrameRemoveListener(
	const base::Callback<void(RenderFrameHost*)>& on_frame_removed) {
	on_frame_removed_ = on_frame_removed;
	}

	RenderViewHostImpl* FrameTree::CreateRenderViewHost(SiteInstance* site_instance,
	int routing_id,
	int main_frame_routing_id,
	bool swapped_out,
	bool hidden) {
	DCHECK(main_frame_routing_id != MSG_ROUTING_NONE);
	RenderViewHostMap::iterator iter =
	render_view_host_map_.find(site_instance->GetId());
	if (iter != render_view_host_map_.end()) {
	// If a RenderViewHost's main frame is pending deletion for this
	// \|site_instance\|, put it in the map of RenderViewHosts pending shutdown.
	// Otherwise return the existing RenderViewHost for the SiteInstance.
	RenderFrameHostImpl* main_frame = static_cast<RenderFrameHostImpl*>(
	iter->second->GetMainFrame());
	if (main_frame->frame_tree_node()->render_manager()->IsPendingDeletion(
	main_frame)) {
	render_view_host_pending_shutdown_map_.insert(
	std::pair<int, RenderViewHostImpl*>(site_instance->GetId(),
	iter->second));
	render_view_host_map_.erase(iter);
	} else {
	return iter->second;
	}
	}
	RenderViewHostImpl* rvh = static_cast<RenderViewHostImpl*>(
	RenderViewHostFactory::Create(site_instance,
	render_view_delegate_,
	render_widget_delegate_,
	routing_id,
	main_frame_routing_id,
	swapped_out,
	hidden));

	render_view_host_map_[site_instance->GetId()] = rvh;
	return rvh;
	}

	RenderViewHostImpl* FrameTree::GetRenderViewHost(SiteInstance* site_instance) {
	RenderViewHostMap::iterator iter =
	render_view_host_map_.find(site_instance->GetId());
	if (iter == render_view_host_map_.end())
	return nullptr;
	return iter->second;
	}

	void FrameTree::AddRenderViewHostRef(RenderViewHostImpl* render_view_host) {
	SiteInstance* site_instance = render_view_host->GetSiteInstance();
	RenderViewHostMap::iterator iter =
	render_view_host_map_.find(site_instance->GetId());
	CHECK(iter != render_view_host_map_.end());
	CHECK(iter->second == render_view_host);

	iter->second->increment_ref_count();
	}

	void FrameTree::ReleaseRenderViewHostRef(RenderViewHostImpl* render_view_host) {
	SiteInstance* site_instance = render_view_host->GetSiteInstance();
	int32 site_instance_id = site_instance->GetId();
	RenderViewHostMap::iterator iter =
	render_view_host_map_.find(site_instance_id);
	if (iter != render_view_host_map_.end() && iter->second == render_view_host) {
	// Decrement the refcount and shutdown the RenderViewHost if no one else is
	// using it.
	CHECK_GT(iter->second->ref_count(), 0);
	iter->second->decrement_ref_count();
	if (iter->second->ref_count() == 0) {
	iter->second->Shutdown();
	render_view_host_map_.erase(iter);
	}
	} else {
	// The RenderViewHost should be in the list of RenderViewHosts pending
	// shutdown.
	bool render_view_host_found = false;
	std::pair<RenderViewHostMultiMap::iterator,
	RenderViewHostMultiMap::iterator> result =
	render_view_host_pending_shutdown_map_.equal_range(site_instance_id);
	for (RenderViewHostMultiMap::iterator multi_iter = result.first;
	multi_iter != result.second;
	++multi_iter) {
	if (multi_iter->second != render_view_host)
	continue;
	render_view_host_found = true;
	// Decrement the refcount and shutdown the RenderViewHost if no one else
	// is using it.
	CHECK_GT(render_view_host->ref_count(), 0);
	render_view_host->decrement_ref_count();
	if (render_view_host->ref_count() == 0) {
	render_view_host->Shutdown();
	render_view_host_pending_shutdown_map_.erase(multi_iter);
	}
	break;
	}
	CHECK(render_view_host_found);
	}
	}

	void FrameTree::FrameRemoved(FrameTreeNode* frame) {
	if (frame->frame_tree_node_id() == focused_frame_tree_node_id_)
	focused_frame_tree_node_id_ = -1;

	// No notification for the root frame.
	if (!frame->parent()) {
	CHECK_EQ(frame, root_.get());
	return;
	}

	// Notify observers of the frame removal.
	if (!on_frame_removed_.is_null())
	on_frame_removed_.Run(frame->current_frame_host());
	}

	void FrameTree::UpdateLoadProgress() {
	double progress = 0.0;
	int frame_count = 0;

	ForEach(base::Bind(&CollectLoadProgress, &progress, &frame_count));
	if (frame_count != 0)
	progress /= frame_count;

	if (progress <= load_progress_)
	return;
	load_progress_ = progress;

	// Notify the WebContents.
	root_->navigator()->GetDelegate()->DidChangeLoadProgress();
	}

	void FrameTree::ResetLoadProgress() {
	ForEach(base::Bind(&ResetNodeLoadProgress));
	load_progress_ = 0.0;
	}

	bool FrameTree::IsLoading() {
	bool is_loading = false;
	ForEach(base::Bind(&IsNodeLoading, &is_loading));
	return is_loading;
	}

	} // namespace content