Remove the is_loading_ field from WebContentsImpl

content/browser/frame_host/render_frame_host_impl.h

Index: content/browser/frame_host/render_frame_host_impl.h
diff --git a/content/browser/frame_host/render_frame_host_impl.h b/content/browser/frame_host/render_frame_host_impl.h
index b457a076e55120811cd6f0c7b214af7d5c936e3a..01c5d759f83fbf5007c18cc7496481b8b1c98588 100644
--- a/content/browser/frame_host/render_frame_host_impl.h
+++ b/content/browser/frame_host/render_frame_host_impl.h
@@ -95,9 +95,9 @@ enum CreateRenderFrameFlags {
   CREATE_RF_HIDDEN = 1 << 1,
 };
 
-class CONTENT_EXPORT RenderFrameHostImpl
-    : public RenderFrameHost,
-      public BrowserAccessibilityDelegate {
+class CONTENT_EXPORT RenderFrameHostImpl : public RenderFrameHost,
+                                           public BrowserAccessibilityDelegate,
+                                           public SiteInstanceImpl::Observer {

[clamy, 2016/01/20 13:23:45]

I tried to get RenderFrameHostManager to properly listen to SiteInstance
notifications about RenderProcessGone for its RenderFrameHosts. Then I realized
that it would be easier to just have the RenderFrameHost listens to its
SiteInstance and reset its load state when the RenderProcess is gone. Wdyt?

[carlosk, 2016/01/20 14:05:14]

Looks better this way.

Note to other reviewers: it's easier to review this change by diffing patch sets
9 and 10.

  public:
   using AXTreeSnapshotCallback =
       base::Callback<void(
@@ -201,6 +201,10 @@ class CONTENT_EXPORT RenderFrameHostImpl
   gfx::AcceleratedWidget AccessibilityGetAcceleratedWidget() override;
   gfx::NativeViewAccessible AccessibilityGetNativeViewAccessible() override;
 
+  // SiteInstanceImpl::Observer
+  void ActiveFrameCountIsZero(SiteInstanceImpl* site_instance) override;
+  void RenderProcessGone(SiteInstanceImpl* site_instance) override;
+
   // Creates a RenderFrame in the renderer process.
   bool CreateRenderFrame(int proxy_routing_id,
                          int opener_routing_id,
@@ -523,6 +527,10 @@ class CONTENT_EXPORT RenderFrameHostImpl
   // Returns the Mojo ImageDownloader service.
   const image_downloader::ImageDownloaderPtr& GetMojoImageDownloader();
 
+  // Resets the loading state. Following this call, the RenderFrameHost will be
+  // in a non-loading state.
+  void ResetLoadingState();
+
  protected:
   friend class RenderFrameHostFactory;
 
@@ -568,7 +576,6 @@ class CONTENT_EXPORT RenderFrameHostImpl
       const base::string16& error_description,
       bool was_ignored_by_handler);
   void OnDidCommitProvisionalLoad(const IPC::Message& msg);
-  void OnDidDropNavigation();
   void OnUpdateState(const PageState& state);
   void OnBeforeUnloadACK(
       bool proceed,