Prepare for per frame did{Start,Stop}Loading calls

content/renderer/render_frame_impl.h

Index: content/renderer/render_frame_impl.h
diff --git a/content/renderer/render_frame_impl.h b/content/renderer/render_frame_impl.h
index 1004340a817b3da03bef50dec1636e3eff152cbf..b7333ba50934dbf0df573439066a90b1aa3cea52 100644
--- a/content/renderer/render_frame_impl.h
+++ b/content/renderer/render_frame_impl.h
@@ -99,8 +99,9 @@ class CONTENT_EXPORT RenderFrameImpl
   // TODO(nasko): Those are page-level methods at this time and come from
   // WebViewClient. We should move them to be WebFrameClient calls and put
   // logic in the browser side to balance starts/stops.
-  void didStartLoading();
-  void didStopLoading();
+  virtual void didStartLoading(bool to_different_document);
+  virtual void didStopLoading();
+  virtual void didChangeLoadProgress(double load_progress);
 
 #if defined(ENABLE_PLUGINS)
   // Notification that a PPAPI plugin has been created.
@@ -401,6 +402,7 @@ class CONTENT_EXPORT RenderFrameImpl
 
   base::WeakPtr<RenderViewImpl> render_view_;
   int routing_id_;
+  bool is_loading_;
   bool is_swapped_out_;
   bool is_detaching_;