ResourceScheduler should use renderer notifications instead of MRUCache to track renderers.

content/browser/loader/resource_dispatcher_host_impl.h

Index: content/browser/loader/resource_dispatcher_host_impl.h
diff --git a/content/browser/loader/resource_dispatcher_host_impl.h b/content/browser/loader/resource_dispatcher_host_impl.h
index 0627227c2b05e7ba192454acc8d5e7bd6e3325c2..fd3285100fefcb2ee69f3a6a2e6051baed54fe87 100644
--- a/content/browser/loader/resource_dispatcher_host_impl.h
+++ b/content/browser/loader/resource_dispatcher_host_impl.h
@@ -28,6 +28,7 @@
 #include "content/browser/loader/resource_loader.h"
 #include "content/browser/loader/resource_loader_delegate.h"
 #include "content/browser/loader/resource_scheduler.h"
+#include "content/browser/loader/resource_scheduler_view_observer.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/child_process_data.h"
 #include "content/public/browser/download_id.h"
@@ -435,7 +436,8 @@ class CONTENT_EXPORT ResourceDispatcherHostImpl
                    ObserverList<ResourceMessageDelegate>*> DelegateMap;
   DelegateMap delegate_map_;
 
-  scoped_ptr<ResourceScheduler> scheduler_;
+  scoped_ptr<ResourceScheduler> scheduler_;  // Lives on IO thread.
+  ResourceSchedulerViewObserver scheduler_observer_;  // Lives on UI thread.
 
   DISALLOW_COPY_AND_ASSIGN(ResourceDispatcherHostImpl);
 };