Introduce a notification to trigger memory purging on the IO thread and use it in ChromeAppCacheService.

TEST=manual
BUG=none

Review URL: http://codereview.chromium.org/547016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@36181 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 39 insertions, 1 deletions

diff --git a/chrome/browser/memory_purger.cc b/chrome/browser/memory_purger.cc
index d230e45..fa85c66 100644
--- a/chrome/browser/memory_purger.cc
+++ b/chrome/browser/memory_purger.cc
@@ -16,6 +16,7 @@
 #include "chrome/browser/renderer_host/resource_dispatcher_host.h"
 #include "chrome/browser/safe_browsing/safe_browsing_service.h"
 #include "chrome/browser/webdata/web_data_service.h"
+#include "chrome/common/notification_service.h"
 #include "chrome/common/render_messages.h"
 #include "net/proxy/proxy_resolver.h"
 #include "net/url_request/url_request_context.h"
@@ -67,6 +68,12 @@ void PurgeMemoryIOHelper::PurgeMemoryOnIOThread() {
   // Close the Safe Browsing database, freeing memory used to cache sqlite as
   // well as a number of in-memory structures.
   safe_browsing_service_->CloseDatabase();
+
+  // The appcache service listens for this notification.
+  NotificationService::current()->Notify(
+      NotificationType::PURGE_MEMORY,
+      Source<void>(NULL),
+      NotificationService::NoDetails());
 }
 
 // -----------------------------------------------------------------------------
diff --git a/chrome/common/appcache/chrome_appcache_service.cc b/chrome/common/appcache/chrome_appcache_service.cc
index c1016cb..cb1f7a3 100644
--- a/chrome/common/appcache/chrome_appcache_service.cc
+++ b/chrome/common/appcache/chrome_appcache_service.cc
@@ -7,6 +7,7 @@
 #include "base/file_path.h"
 #include "chrome/browser/chrome_thread.h"
 #include "chrome/common/chrome_constants.h"
+#include "chrome/common/notification_service.h"
 #include "webkit/appcache/appcache_thread.h"
 
 static bool has_initialized_thread_ids;
@@ -20,12 +21,22 @@ ChromeAppCacheService::ChromeAppCacheService(const FilePath& data_directory,
   }
   Initialize(is_incognito ? FilePath()
                           : data_directory.Append(chrome::kAppCacheDirname));
+
+  registrar_.Add(
+      this, NotificationType::PURGE_MEMORY, NotificationService::AllSources());
 }
 
 ChromeAppCacheService::~ChromeAppCacheService() {
   DCHECK(ChromeThread::CurrentlyOn(ChromeThread::IO));
 }
 
+void ChromeAppCacheService::Observe(NotificationType type,
+                                    const NotificationSource& source,
+                                    const NotificationDetails& details) {
+  DCHECK(type == NotificationType::PURGE_MEMORY);
+  PurgeMemory();
+}
+
 static ChromeThread::ID ToChromeThreadID(int id) {
   DCHECK(has_initialized_thread_ids);
   DCHECK(id == ChromeThread::DB || id == ChromeThread::IO);
diff --git a/chrome/common/appcache/chrome_appcache_service.h b/chrome/common/appcache/chrome_appcache_service.h
index 509afd2..a202601 100644
--- a/chrome/common/appcache/chrome_appcache_service.h
+++ b/chrome/common/appcache/chrome_appcache_service.h
@@ -6,6 +6,7 @@
 #define CHROME_COMMON_APPCACHE_CHROME_APPCACHE_SERVICE_H_
 
 #include "base/ref_counted.h"
+#include "chrome/common/notification_registrar.h"
 #include "webkit/appcache/appcache_service.h"
 
 class FilePath;
@@ -20,13 +21,21 @@ class FilePath;
 // the IO thread.
 class ChromeAppCacheService
     : public base::RefCounted<ChromeAppCacheService>,
-      public appcache::AppCacheService {
+      public appcache::AppCacheService,
+      public NotificationObserver {
  public:
   ChromeAppCacheService(const FilePath& data_directory,
                         bool is_incognito);
  private:
   friend class base::RefCounted<ChromeAppCacheService>;
   virtual ~ChromeAppCacheService();
+
+  // NotificationObserver override
+  virtual void Observe(NotificationType type,
+                       const NotificationSource& source,
+                       const NotificationDetails& details);
+
+  NotificationRegistrar registrar_;
 };
 
 #endif  // CHROME_COMMON_APPCACHE_CHROME_APPCACHE_SERVICE_H_
diff --git a/chrome/common/notification_type.h b/chrome/common/notification_type.h
index d88b97e..d021059 100644
--- a/chrome/common/notification_type.h
+++ b/chrome/common/notification_type.h
@@ -794,6 +794,12 @@ class NotificationType {
     // key of the entry that was affected.
     AUTOFILL_ENTRIES_CHANGED,
 
+    // Purge Memory ------------------------------------------------------------
+
+    // Sent on the IO thread when the system should try to reduce the amount of
+    // memory in use, no source or details are passed. See memory_purger.h .cc.
+    PURGE_MEMORY,
+
     // Count (must be last) ----------------------------------------------------
     // Used to determine the number of notification types.  Not valid as
     // a type parameter when registering for or posting notifications.
diff --git a/webkit/appcache/appcache_service.h b/webkit/appcache/appcache_service.h
index 05e9329..986e620 100644
--- a/webkit/appcache/appcache_service.h
+++ b/webkit/appcache/appcache_service.h
@@ -26,6 +26,11 @@ class AppCacheService {
 
   void Initialize(const FilePath& cache_directory);
 
+  void PurgeMemory() {
+    if (storage_.get())
+      storage_->PurgeMemory();
+  }
+
   // Context for use during cache updates, should only be accessed
   // on the IO thread. We do NOT add a reference to the request context,
   // it is the callers responsibility to ensure that the pointer