Move LoadProgressTracker to the browser process.

content/browser/frame_host/render_frame_host_delegate.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_DELEGATE_H_
 #define CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_DELEGATE_H_
 
 #include "base/basictypes.h"
 #include "content/common/content_export.h"
 #include "content/public/common/javascript_message_type.h"
@@ skipping 26 matching lines @@
                                    const base::string16& message,
                                    int32 line_no,
                                    const base::string16& source_id);
 
   // Informs the delegate whenever a RenderFrameHost is created.
   virtual void RenderFrameCreated(RenderFrameHost* render_frame_host) {}
 
   // Informs the delegate whenever a RenderFrameHost is deleted.
   virtual void RenderFrameDeleted(RenderFrameHost* render_frame_host) {}
 
-  // The top-level 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.
+  // The top-level RenderFrame began loading a new page. The presence of this
+  // function in RenderFrameHostDelegate is a hack to allow the RenderFrameHost
+  // to force a loading spinner to show up; TODO(avi): Remove this.

[nasko, 2014/05/05 23:51:12]

I'm not sure that this is a hack. It seems this is used to intentionally
indicate that a load has started as soon as possible in the case of
browser-initiated navigation. 

[Avi (use Gerrit), 2014/05/06 00:03:40]

It feels unbalanced to me. At points we have to force the UI to stop too, and it
doesn't flow well.

I'll revert this comment, but the current structure feels off.

   virtual void DidStartLoading(RenderFrameHost* render_frame_host,
                                bool to_different_document) {}
 
-  // The top-level RenderFrame stopped loading a page. This corresponds to
-  // Blink's notion of the throbber stopping.
-  virtual void DidStopLoading(RenderFrameHost* render_frame_host) {}
-
   // The RenderFrameHost has been swapped out.
   virtual void SwappedOut(RenderFrameHost* render_frame_host) {}
 
   // Notification that a worker process has crashed.
   virtual void WorkerCrashed(RenderFrameHost* render_frame_host) {}
 
   // A context menu should be shown, to be built using the context information
   // provided in the supplied params.
   virtual void ShowContextMenu(RenderFrameHost* render_frame_host,
                                const ContextMenuParams& params) {}
@@ skipping 28 matching lines @@
   // not a WebContents, returns NULL.
   virtual WebContents* GetAsWebContents();
 
  protected:
   virtual ~RenderFrameHostDelegate() {}
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_RENDER_FRAME_HOST_DELEGATE_H_