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 3c5e3acef27fc9a7c88709200b1ec36bf68e9f28..eea9f321c4ff3ea23a0f239dd333cf69f853e79d 100644
--- a/content/browser/frame_host/render_frame_host_impl.h
+++ b/content/browser/frame_host/render_frame_host_impl.h
@@ -16,8 +16,10 @@ class GURL;
 namespace content {
 
 class FrameTree;
+class FrameTreeNode;
 class RenderProcessHost;
 class RenderViewHostImpl;
+class SiteInstance;
 
 class CONTENT_EXPORT RenderFrameHostImpl : public RenderFrameHost {
  public:
@@ -33,6 +35,7 @@ class CONTENT_EXPORT RenderFrameHostImpl : public RenderFrameHost {
 
   void Init();
   RenderProcessHost* GetProcess() const;
+  SiteInstance* GetSiteInstance() const;
   int routing_id() const { return routing_id_; }
   void OnCreateChildFrame(int new_frame_routing_id,
                           int64 parent_frame_id,
@@ -51,10 +54,13 @@ class CONTENT_EXPORT RenderFrameHostImpl : public RenderFrameHost {
   // into WebContentsObserver::FrameDetached for now.
   RenderFrameHostImpl(RenderViewHostImpl* render_view_host,
                       FrameTree* frame_tree,
+                      FrameTreeNode* frame_tree_node,
                       int routing_id,
                       bool is_swapped_out);
 
  private:
+  friend class TestRenderViewHost;
+
   // IPC Message handlers.
   void OnDetach(int64 parent_frame_id, int64 frame_id);
   void OnDidStartProvisionalLoadForFrame(int64 frame_id,
@@ -71,6 +77,10 @@ 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 FrameTreeNode which this RenderFrameHostImpl is hosted in.
+  FrameTreeNode* frame_tree_node_;
+
   int routing_id_;
   bool is_swapped_out_;