Remove the unmaintained performance monitor.

content/browser/frame_host/navigator_impl.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_NAVIGATOR_IMPL_H_
 #define CONTENT_BROWSER_FRAME_HOST_NAVIGATOR_IMPL_H_
 
 #include "base/memory/ref_counted.h"
 #include "content/browser/frame_host/navigation_controller_impl.h"
 #include "content/browser/frame_host/navigator.h"
@@ skipping 40 matching lines @@
       int32 page_id,
       const GURL& source_url,
       const GURL& target_url) OVERRIDE;
   virtual void DidNavigate(
       RenderFrameHostImpl* render_frame_host,
       const FrameHostMsg_DidCommitProvisionalLoad_Params&
           input_params) OVERRIDE;
   virtual bool NavigateToPendingEntry(
       RenderFrameHostImpl* render_frame_host,
       NavigationController::ReloadType reload_type) OVERRIDE;
-  virtual base::TimeTicks GetCurrentLoadStart() OVERRIDE;
   virtual void RequestOpenURL(RenderFrameHostImpl* render_frame_host,
                               const GURL& url,
                               const Referrer& referrer,
                               WindowOpenDisposition disposition,
                               bool should_replace_current_entry,
                               bool user_gesture) OVERRIDE;
   virtual void RequestTransferURL(
       RenderFrameHostImpl* render_frame_host,
       const GURL& url,
       const std::vector<GURL>& redirect_chain,
@@ skipping 26 matching lines @@
   // The NavigationController that will keep track of session history for all
   // RenderFrameHost objects using this NavigatorImpl.
   // TODO(nasko): Move ownership of the NavigationController from
   // WebContentsImpl to this class.
   NavigationControllerImpl* controller_;
 
   // Used to notify the object embedding this Navigator about navigation
   // events. Can be NULL in tests.
   NavigatorDelegate* delegate_;
 
-  // System time at which the current load was started.
-  base::TimeTicks current_load_start_;
-
   DISALLOW_COPY_AND_ASSIGN(NavigatorImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_NAVIGATOR_IMPL_H_