Add functionality to the renderer thread to purge memory. Not yet called....

chrome/renderer/render_thread.h

 // Copyright (c) 2009 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_RENDER_THREAD_H_
 #define CHROME_RENDERER_RENDER_THREAD_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 156 matching lines @@
   void OnSetCacheCapacities(size_t min_dead_capacity,
                             size_t max_dead_capacity,
                             size_t capacity);
   void OnGetCacheResourceStats();
 
   // Send all histograms to browser.
   void OnGetRendererHistograms(int sequence_number);
 
   void OnExtensionMessageInvoke(const std::string& function_name,
                                 const ListValue& args);
+  void OnPurgeMemory();
   void OnPurgePluginListCache(bool reload_pages);
 
   // Gather usage statistics from the in-memory cache and inform our host.
   // These functions should be call periodically so that the host can make
   // decisions about how to allocation resources using current information.
   void InformHostOfCacheStats();
 
   // We initialize WebKit as late as possible.
   void EnsureWebKitInitialized();
 
@@ skipping 30 matching lines @@
   // The count of hidden RenderWidgets running through this thread.
   int hidden_widget_count_;
 
   // The current value of the idle notification timer delay.
   double idle_notification_delay_in_s_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderThread);
 };
 
 #endif  // CHROME_RENDERER_RENDER_THREAD_H_