[Mac] Maximise timer slack for background tabs

chrome/renderer/chrome_render_process_observer.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_RENDERER_CHROME_RENDER_PROCESS_OBSERVER_H_
 #define CHROME_RENDERER_CHROME_RENDER_PROCESS_OBSERVER_H_
 
 #include <string>
 
 #include "base/compiler_specific.h"
@@ skipping 33 matching lines @@
  private:
   // RenderProcessObserver implementation.
   virtual bool OnControlMessageReceived(const IPC::Message& message) OVERRIDE;
   virtual void WebKitInitialized() OVERRIDE;
   virtual void OnRenderProcessShutdown() OVERRIDE;
 
   void OnSetIsIncognitoProcess(bool is_incognito_process);
   void OnSetContentSettingsForCurrentURL(
       const GURL& url, const ContentSettings& content_settings);
   void OnSetContentSettingRules(const RendererContentSettingRules& rules);
+  void OnSetTimerCoalescing(bool enabled);
   void OnSetCacheCapacities(size_t min_dead_capacity,
                             size_t max_dead_capacity,
                             size_t capacity);
   // If |on_navigation| is true, the clearing is delayed until the next
   // navigation event.
   void OnClearCache(bool on_navigation);
   void OnGetCacheResourceStats();
   void OnSetFieldTrialGroup(const std::string& fiel_trial_name,
                             const std::string& group_name);
   void OnGetV8HeapStats();
 
   static bool is_incognito_process_;
   scoped_ptr<content::ResourceDispatcherDelegate> resource_delegate_;
   ChromeContentRendererClient* client_;
   // If true, the web cache shall be cleared before the next navigation event.
   bool clear_cache_pending_;
   RendererContentSettingRules content_setting_rules_;
 
   bool webkit_initialized_;
   size_t pending_cache_min_dead_capacity_;
   size_t pending_cache_max_dead_capacity_;
   size_t pending_cache_capacity_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeRenderProcessObserver);
 };
 
 #endif  // CHROME_RENDERER_CHROME_RENDER_PROCESS_OBSERVER_H_