Move LoadProgressTracker to the browser process.

content/browser/frame_host/navigator.h

Index: content/browser/frame_host/navigator.h
diff --git a/content/browser/frame_host/navigator.h b/content/browser/frame_host/navigator.h
index b229ffb97f2dbaa1901b2cf7e270cd0595d39338..15f7abd8a7835e941386d971c6f6c75f0a2f3857 100644
--- a/content/browser/frame_host/navigator.h
+++ b/content/browser/frame_host/navigator.h
@@ -37,6 +37,9 @@ class CONTENT_EXPORT Navigator : public base::RefCounted<Navigator> {
   // Returns the NavigationController associated with this Navigator.
   virtual NavigationController* GetController();
 
+
+  // Notifications coming from the RenderFrameHosts ----------------------------
+
   // The RenderFrameHostImpl started a provisional load.
   virtual void DidStartProvisionalLoad(RenderFrameHostImpl* render_frame_host,
                                        int parent_routing_id,
@@ -88,6 +91,24 @@ class CONTENT_EXPORT Navigator : public base::RefCounted<Navigator> {
       RenderFrameHostImpl* render_frame_host,
       NavigationController::ReloadType reload_type);
 
+  // The RenderFrame began loading a new page. This corresponds to Blink's
+  // notion of the throbber starting.
+  // |to_different_document| will be true unless the load is a fragment
+  // navigation, or triggered by history.pushState/replaceState.
+  virtual void DidStartLoading(RenderFrameHostImpl* render_frame_host,
+                               bool to_different_document) {}
+
+  // The RenderFrame stopped loading a page. This corresponds to Blink's notion
+  // of the throbber stopping.
+  virtual void DidStopLoading(RenderFrameHostImpl* render_frame_host) {}
+
+  // The RenderFrame reported making progress in a load.
+  virtual void DidChangeLoadProgress(RenderFrameHostImpl* render_frame_host,
+                                     double load_progress) {}
+
+
+  // Navigation requests -------------------------------------------------------
+
   virtual base::TimeTicks GetCurrentLoadStart();
 
   // The RenderFrameHostImpl has received a request to open a URL with the