Forward handling of low-mem message to the content renderer client. Add APIs to handle this case.

chrome/renderer/chrome_render_process_observer.cc

 // Copyright (c) 2011 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/chrome_render_process_observer.h"
 
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
 #include "base/native_library.h"
 #include "base/path_service.h"
 #include "base/process_util.h"
 #include "base/threading/platform_thread.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/extension_localization_peer.h"
 #include "chrome/common/net/net_resource_provider.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/renderer/content_settings_observer.h"
 #include "chrome/renderer/security_filter_peer.h"
+#include "content/common/notification_source.h"
 #include "content/common/resource_dispatcher.h"
 #include "content/common/resource_dispatcher_delegate.h"
 #include "content/common/view_messages.h"
 #include "content/renderer/render_thread.h"
 #include "content/renderer/render_view.h"
 #include "content/renderer/render_view_visitor.h"
 #include "crypto/nss_util.h"
 #include "media/base/media.h"
 #include "media/base/media_switches.h"
 #include "net/base/net_errors.h"
@@ skipping 352 matching lines @@
   std::string error;
   base::LoadNativeLibrary(FilePath(L"crypt32.dll"), &error);
 #endif
 
   // Note that under Linux, the media library will normally already have
   // been initialized by the Zygote before this instance became a Renderer.
   FilePath media_path;
   PathService::Get(chrome::DIR_MEDIA_LIBS, &media_path);
   if (!media_path.empty())
     media::InitializeMediaLibrary(media_path);
+
+  registrar_.Add(this, content::NOTIFICATION_PURGE_MEMORY, Source<void>(NULL));
 }
 
 ChromeRenderProcessObserver::~ChromeRenderProcessObserver() {
 }
 
 bool ChromeRenderProcessObserver::OnControlMessageReceived(
     const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(ChromeRenderProcessObserver, message)
     IPC_MESSAGE_HANDLER(ViewMsg_SetIsIncognitoProcess, OnSetIsIncognitoProcess)
     IPC_MESSAGE_HANDLER(ViewMsg_SetDefaultContentSettings,
                         OnSetDefaultContentSettings)
     IPC_MESSAGE_HANDLER(ViewMsg_SetContentSettingsForCurrentURL,
                         OnSetContentSettingsForCurrentURL)
     IPC_MESSAGE_HANDLER(ViewMsg_SetCacheCapacities, OnSetCacheCapacities)
     IPC_MESSAGE_HANDLER(ViewMsg_ClearCache, OnClearCache)
     IPC_MESSAGE_HANDLER(ViewMsg_SetFieldTrialGroup, OnSetFieldTrialGroup)
 #if defined(USE_TCMALLOC)
     IPC_MESSAGE_HANDLER(ViewMsg_GetRendererTcmalloc, OnGetRendererTcmalloc)
 #endif
     IPC_MESSAGE_HANDLER(ViewMsg_GetV8HeapStats, OnGetV8HeapStats)
     IPC_MESSAGE_HANDLER(ViewMsg_GetCacheResourceStats, OnGetCacheResourceStats)
-    IPC_MESSAGE_HANDLER(ViewMsg_PurgeMemory, OnPurgeMemory)
     IPC_MESSAGE_UNHANDLED(handled = false)
   IPC_END_MESSAGE_MAP()
   return handled;
 }
 
 void ChromeRenderProcessObserver::WebKitInitialized() {
   WebRuntimeFeatures::enableMediaPlayer(media::IsMediaLibraryInitialized());
 }
 
 void ChromeRenderProcessObserver::OnSetIsIncognitoProcess(
@@ skipping 47 matching lines @@
   base::FieldTrialList::CreateFieldTrial(field_trial_name, group_name);
 }
 
 void ChromeRenderProcessObserver::OnGetV8HeapStats() {
   v8::HeapStatistics heap_stats;
   v8::V8::GetHeapStatistics(&heap_stats);
   Send(new ViewHostMsg_V8HeapStats(heap_stats.total_heap_size(),
                                    heap_stats.used_heap_size()));
 }
 
+void ChromeRenderProcessObserver::Observe(int type,
+                                          const NotificationSource& source,
+                                          const NotificationDetails& details) {
+  if (type == content::NOTIFICATION_PURGE_MEMORY)
+    OnPurgeMemory();
+}
+
 void ChromeRenderProcessObserver::OnPurgeMemory() {
+  LOG(INFO) << "CRPO purging memory!";
   // 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();
 
   // Release all freeable memory from the SQLite process-global page cache (a
   // low-level object which backs the Connection-specific page caches).
   while (sqlite3_release_memory(std::numeric_limits<int>::max()) > 0) {
   }
 
   // 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_MACOSX) && defined(USE_TCMALLOC)
   // Tell tcmalloc to release any free pages it's still holding.
   MallocExtension::instance()->ReleaseFreeMemory();
 #endif
 }