Move out DidStartProvisionalLoad from WebContentsImpl into Navigator.

content/browser/renderer_host/render_view_host_impl.cc

Index: content/browser/renderer_host/render_view_host_impl.cc
diff --git a/content/browser/renderer_host/render_view_host_impl.cc b/content/browser/renderer_host/render_view_host_impl.cc
index bb6635ff536889f2b9591a30637e8079f5724f70..76be6d09e4e853cbe59c430bc6f741b13f3b3d77 100644
--- a/content/browser/renderer_host/render_view_host_impl.cc
+++ b/content/browser/renderer_host/render_view_host_impl.cc
@@ -191,7 +191,10 @@ RenderViewHostImpl::RenderViewHostImpl(
     main_frame_routing_id = GetProcess()->GetNextRoutingID();
 
   main_render_frame_host_ = RenderFrameHostFactory::Create(
-      this, delegate_->GetFrameTree(), main_frame_routing_id, is_swapped_out_);
+      this, delegate_->GetFrameTree(), delegate_->GetFrameTree()->root(),
+      main_frame_routing_id, is_swapped_out_);
+  delegate_->GetFrameTree()->root()->set_render_frame_host(
+      main_render_frame_host_.get(), false);
 
   GetProcess()->EnableSendQueue();
 
@@ -1398,8 +1401,7 @@ void RenderViewHostImpl::OnDidStartProvisionalLoadForFrame(
     int64 parent_frame_id,
     bool is_main_frame,
     const GURL& url) {
-  delegate_->DidStartProvisionalLoadForFrame(
-      this, frame_id, parent_frame_id, is_main_frame, url);
+  NOTREACHED();
 }
 
 void RenderViewHostImpl::OnDidRedirectProvisionalLoad(