Move out DidStartProvisionalLoad from WebContentsImpl into Navigator.

content/browser/renderer_host/frame_tree_node.h

Index: content/browser/renderer_host/frame_tree_node.h
diff --git a/content/browser/renderer_host/frame_tree_node.h b/content/browser/renderer_host/frame_tree_node.h
index bfede18fe0b84759b53de48c29a437a2a47ce126..68f36f4845b7967640bc816165d7f6389ff8b72c 100644
--- a/content/browser/renderer_host/frame_tree_node.h
+++ b/content/browser/renderer_host/frame_tree_node.h
@@ -15,6 +15,7 @@
 
 namespace content {
 
+class Navigator;
 class RenderFrameHostImpl;
 
 // When a page contains iframes, its renderer process maintains a tree structure
@@ -25,7 +26,9 @@ class CONTENT_EXPORT FrameTreeNode {
  public:
   static const int64 kInvalidFrameId;
 
-  FrameTreeNode(int64 frame_id, const std::string& name,
+  FrameTreeNode(Navigator* navigator,
+                int64 frame_id,
+                const std::string& name,
                 scoped_ptr<RenderFrameHostImpl> render_frame_host);
   ~FrameTreeNode();
 
@@ -75,6 +78,11 @@ class CONTENT_EXPORT FrameTreeNode {
     return render_frame_host_;
   }
 
+  Navigator* navigator() {
+    return navigator_;
+  }
+
+
  private:
   // The unique identifier for the frame in the page.
   int64 frame_id_;
@@ -86,6 +94,10 @@ class CONTENT_EXPORT FrameTreeNode {
   // The immediate children of this specific frame.
   ScopedVector<FrameTreeNode> children_;
 
+  // Used to perform navigation in the RenderFrameHosts associated with this
+  // FrameTreeNode. Owned by FrameTree.
+  Navigator* navigator_;
+
   // When ResetForMainFrame() is called, this is set to false and the
   // |render_frame_host_| below is not deleted on destruction.
   //