Move out DidStartProvisionalLoad from WebContentsImpl into Navigator.

content/browser/renderer_host/frame_tree.cc

Index: content/browser/renderer_host/frame_tree.cc
diff --git a/content/browser/renderer_host/frame_tree.cc b/content/browser/renderer_host/frame_tree.cc
index 620da918c4b2fd1b54e897979f24951e0b033fca..5fcffdfea33a0817ec9d5f863a6a1dbf54957767 100644
--- a/content/browser/renderer_host/frame_tree.cc
+++ b/content/browser/renderer_host/frame_tree.cc
@@ -9,6 +9,7 @@
 #include "base/bind.h"
 #include "base/callback.h"
 #include "content/browser/renderer_host/frame_tree_node.h"
+#include "content/browser/renderer_host/navigator.h"
 #include "content/browser/renderer_host/render_frame_host_impl.h"
 
 namespace content {
@@ -28,9 +29,15 @@ bool FrameTreeNodeForId(int64 frame_id, FrameTreeNode** out_node,
 
 }  // namespace
 
-FrameTree::FrameTree()
-    : root_(new FrameTreeNode(FrameTreeNode::kInvalidFrameId, std::string(),
-                              scoped_ptr<RenderFrameHostImpl>())) {
+FrameTree::FrameTree() {}
+
+void FrameTree::Init(
+    NavigationControllerImpl* navigation_controller,
+    NavigatorObserver* navigator_observer) {
+  navigator_.reset(new Navigator(navigation_controller, navigator_observer));
+  root_.reset(new FrameTreeNode(navigator_.get(),
+                                FrameTreeNode::kInvalidFrameId, std::string(),
+                                scoped_ptr<RenderFrameHostImpl>()));
 }
 
 FrameTree::~FrameTree() {
@@ -131,7 +138,8 @@ scoped_ptr<FrameTreeNode> FrameTree::CreateNode(
       new RenderFrameHostImpl(root_->render_frame_host()->render_view_host(),
                               this, render_frame_host_id, false));
 
-  return make_scoped_ptr(new FrameTreeNode(frame_id, frame_name,
+  return make_scoped_ptr(new FrameTreeNode(navigator_.get(),
+                                           frame_id, frame_name,
                                            render_frame_host.Pass()));
 }