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

chrome/renderer/render_thread.cc

 // 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.
 
 #include "chrome/renderer/render_thread.h"
 
 #include <algorithm>
 #include <map>
 #include <vector>
 
@@ skipping 28 matching lines @@
 #include "chrome/renderer/external_extension.h"
 #include "chrome/renderer/loadtimes_extension_bindings.h"
 #include "chrome/renderer/net/render_dns_master.h"
 #include "chrome/renderer/render_process.h"
 #include "chrome/renderer/render_view.h"
 #include "chrome/renderer/renderer_webkitclient_impl.h"
 #include "chrome/renderer/user_script_slave.h"
 #include "ipc/ipc_message.h"
 #include "webkit/api/public/WebCache.h"
 #include "webkit/api/public/WebColor.h"
+#include "webkit/api/public/WebCrossOriginPreflightResultCache.h"
+#include "webkit/api/public/WebFontCache.h"
+#include "webkit/api/public/WebColor.h"
 #include "webkit/api/public/WebKit.h"
 #include "webkit/api/public/WebStorageEventDispatcher.h"
 #include "webkit/api/public/WebString.h"
 #include "webkit/extensions/v8/benchmarking_extension.h"
 #include "webkit/extensions/v8/gears_extension.h"
 #include "webkit/extensions/v8/interval_extension.h"
 #include "webkit/extensions/v8/playback_extension.h"
 #include "third_party/tcmalloc/tcmalloc/src/google/malloc_extension.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #include <objbase.h>
 #endif
 
 using WebKit::WebCache;
+using WebKit::WebCrossOriginPreflightResultCache;
+using WebKit::WebFontCache;
 using WebKit::WebString;
 using WebKit::WebStorageEventDispatcher;
 
 namespace {
 static const unsigned int kCacheStatsDelayMS = 2000 /* milliseconds */;
 static const double kInitialIdleHandlerDelayS = 1.0 /* seconds */;
 
 static base::LazyInstance<base::ThreadLocalPointer<RenderThread> > lazy_tls(
     base::LINKER_INITIALIZED);
 
@@ skipping 206 matching lines @@
     IPC_MESSAGE_HANDLER(ViewMsg_GetCacheResourceStats,
                         OnGetCacheResourceStats)
     IPC_MESSAGE_HANDLER(ViewMsg_UserScripts_UpdatedScripts,
                         OnUpdateUserScripts)
     // TODO(rafaelw): create an ExtensionDispatcher that handles extension
     // messages seperates their handling from the RenderThread.
     IPC_MESSAGE_HANDLER(ViewMsg_ExtensionMessageInvoke,
                         OnExtensionMessageInvoke)
     IPC_MESSAGE_HANDLER(ViewMsg_Extension_SetFunctionNames,
                         OnSetExtensionFunctionNames)
+    IPC_MESSAGE_HANDLER(ViewMsg_PurgeMemory, OnPurgeMemory)
     IPC_MESSAGE_HANDLER(ViewMsg_PurgePluginListCache,
                         OnPurgePluginListCache)
     IPC_MESSAGE_HANDLER(ViewMsg_Extension_UpdatePageActions,
                         OnPageActionsUpdated)
     IPC_MESSAGE_HANDLER(ViewMsg_Extension_SetAPIPermissions,
                         OnExtensionSetAPIPermissions)
     IPC_MESSAGE_HANDLER(ViewMsg_Extension_SetHostPermissions,
                         OnExtensionSetHostPermissions)
     IPC_MESSAGE_HANDLER(ViewMsg_DOMStorageEvent,
                         OnDOMStorageEvent)
@@ skipping 202 matching lines @@
   MessageLoop::current()->PostDelayedTask(FROM_HERE,
       task_factory_->NewRunnableMethod(&RenderThread::IdleHandler),
       static_cast<int64>(floor(idle_notification_delay_in_s_)) * 1000);
 }
 
 void RenderThread::OnExtensionMessageInvoke(const std::string& function_name,
                                             const ListValue& args) {
   RendererExtensionBindings::Invoke(function_name, args, NULL);
 }
 
+void RenderThread::OnPurgeMemory() {
+  EnsureWebKitInitialized();
+
+  // Clear the object cache (as much as possible; some live objects cannot be
+  // freed).
+  WebCache::clear();
+
+  // Clear the font/glyph cache.
+  WebFontCache::clear();
+
+  // Clear the Cross-Origin Preflight cache.
+  WebCrossOriginPreflightResultCache::clear();
+
+  // Repeatedly call the V8 idle notification until it returns true ("nothing
+  // more to free").  Note that it makes more sense to do this than to implement
+  // a new "delete everything" pass because object references make it difficult
+  // to free everything possible in just one pass.
+  while (!v8::V8::IdleNotification())
+    ;
+
+#if defined(OS_WIN)
+  // Tell tcmalloc to release any free pages it's still holding.
+  MallocExtension::instance()->ReleaseFreeMemory();
+#endif
+}
+
 void RenderThread::OnPurgePluginListCache(bool reload_pages) {
   EnsureWebKitInitialized();
   // The call below will cause a GetPlugins call with refresh=true, but at this
   // point we already know that the browser has refreshed its list, so disable
   // refresh temporarily to prevent each renderer process causing the list to be
   // regenerated.
   plugin_refresh_allowed_ = false;
   WebKit::resetPluginCache(reload_pages);
   plugin_refresh_allowed_ = true;
 }