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

chrome/renderer/chrome_render_process_observer.h

Index: chrome/renderer/chrome_render_process_observer.h
diff --git a/chrome/renderer/chrome_render_process_observer.h b/chrome/renderer/chrome_render_process_observer.h
index beb2b2687932571f7ab1f068b8b5f36c40d14140..1f465932a137f7d4c75d9875d3d51b57a18c395d 100644
--- a/chrome/renderer/chrome_render_process_observer.h
+++ b/chrome/renderer/chrome_render_process_observer.h
@@ -10,6 +10,8 @@
 
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
+#include "content/common/notification_observer.h"
+#include "content/common/notification_registrar.h"
 #include "content/renderer/render_process_observer.h"
 
 class GURL;
@@ -20,13 +22,19 @@ struct ContentSettings;
 // a RenderView) for Chrome specific messages that the content layer doesn't
 // happen.  If a few messages are related, they should probably have their own
 // observer.
-class ChromeRenderProcessObserver : public RenderProcessObserver {
+class ChromeRenderProcessObserver : public RenderProcessObserver,
+                                    public NotificationObserver {
  public:
   ChromeRenderProcessObserver();
   virtual ~ChromeRenderProcessObserver();
 
   static bool is_incognito_process() { return is_incognito_process_; }
 
+  // NotificationObserver
+  void Observe(int type,
+               const NotificationSource& source,
+               const NotificationDetails& details) OVERRIDE;
+
  private:
   // RenderProcessObserver implementation.
   virtual bool OnControlMessageReceived(const IPC::Message& message) OVERRIDE;
@@ -50,6 +58,8 @@ class ChromeRenderProcessObserver : public RenderProcessObserver {
   static bool is_incognito_process_;
   scoped_ptr<ResourceDispatcherDelegate> resource_delegate_;
 
+  NotificationRegistrar registrar_;
+
   DISALLOW_COPY_AND_ASSIGN(ChromeRenderProcessObserver);
 };