Move out DidStartProvisionalLoad from WebContentsImpl into Navigator.

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 dbe8972e2ac3a120d554c8a24fde378d49be2942..35e19d7c08cb66c9f47a563a59aa6432fcb1e0b8 100644
--- a/content/browser/frame_host/render_frame_host_impl.h
+++ b/content/browser/frame_host/render_frame_host_impl.h
@@ -15,8 +15,10 @@ class GURL;
 namespace content {
 
 class FrameTree;
+class Navigator;
 class RenderProcessHost;
 class RenderViewHostImpl;
+class SiteInstance;
 
 class CONTENT_EXPORT RenderFrameHostImpl : public RenderFrameHost {
  public:
@@ -27,6 +29,7 @@ class CONTENT_EXPORT RenderFrameHostImpl : public RenderFrameHost {
   // into WebContentsObserver::FrameDetached for now.
   RenderFrameHostImpl(RenderViewHostImpl* render_view_host,
                       FrameTree* frame_tree,
+                      Navigator* navigator,
                       int routing_id,
                       bool is_swapped_out);
   virtual ~RenderFrameHostImpl();
@@ -37,8 +40,11 @@ class CONTENT_EXPORT RenderFrameHostImpl : public RenderFrameHost {
   // IPC::Listener
   virtual bool OnMessageReceived(const IPC::Message& msg) OVERRIDE;
 
+  // RenderFrameHost
+  virtual RenderProcessHost* GetProcess() const OVERRIDE;
+  virtual SiteInstance* GetSiteInstance() const OVERRIDE;
+
   void Init();
-  RenderProcessHost* GetProcess() const;
   int routing_id() const { return routing_id_; }
   void OnCreateChildFrame(int new_frame_routing_id,
                           int64 parent_frame_id,
@@ -66,6 +72,11 @@ class CONTENT_EXPORT RenderFrameHostImpl : public RenderFrameHost {
   // Allows this RenderFrameHost to add and remove nodes in response to
   // messages from the renderer requesting DOM manipulation.
   FrameTree* frame_tree_;
+
+  // The Navigator object allows the RenderFrameHost to perform navigations
+  // in its own frame in the frame tree. The Navigator is owned by FrameTree.
+  Navigator* navigator_;
+
   int routing_id_;
   bool is_swapped_out_;