Trigger Dangerous indicator for unsafe subresources

Previously, the Dangerous indicator was not firing for subresources
flagged by Safe Browsing as unsafe. This is because marking a
subresource as unsafe was not triggering an omnibox update. We want to
trigger an omnibox update whenever a URL is marked as
whitelisted (either pending, meaning that an interstitial is showing, or
whitelisted, meaning that an interstitial has been clicked through) in
SafeBrowsingUIManager.

To do so, this CL renames WebContentsImpl::DidChangeVisibleSSLState() to
DidChangeVisibleSecurityState() (since it's no longer just SSL
information that can affect the omnibox security UI) and moves it to
WebContents so that it can be called from SafeBrowsingUIManager.

BUG=659713
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_site_isolation

Review-Url: https://codereview.chromium.org/2444383007
Cr-Commit-Position: refs/heads/master@{#428223}
18 files changed