Thumbnails: Add some perf UMA

chrome/browser/thumbnails/thumbnail_tab_helper.h

 // Copyright (c) 2012 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 CHROME_BROWSER_THUMBNAILS_THUMBNAIL_TAB_HELPER_H_
 #define CHROME_BROWSER_THUMBNAILS_THUMBNAIL_TAB_HELPER_H_
 
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
+#include "base/time/time.h"
 #include "chrome/browser/thumbnails/thumbnailing_context.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
 #include "content/public/browser/readback_types.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
 
 namespace content {
 class RenderViewHost;
 class RenderWidgetHost;
@@ skipping 44 matching lines @@
 
   // Called when a render view host was created for a WebContents.
   void RenderViewHostCreated(content::RenderViewHost* renderer);
 
   // Indicates that the given widget has changed is visibility.
   void WidgetHidden(content::RenderWidgetHost* widget);
 
   const bool capture_on_load_finished_;
 
   content::NotificationRegistrar registrar_;
+
+  bool load_interrupted_;
+
   scoped_refptr<thumbnails::ThumbnailingContext> thumbnailing_context_;
 
-  bool load_interrupted_;
+  base::TimeTicks copy_from_surface_start_time_;
+  base::TimeTicks process_bitmap_start_time_;
 
   base::WeakPtrFactory<ThumbnailTabHelper> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ThumbnailTabHelper);
 };
 
 #endif  // CHROME_BROWSER_THUMBNAILS_THUMBNAIL_TAB_HELPER_H_