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..5c5c92d2ddf4c9040f79cf04acfc6214ea38e0b2 100644
--- a/content/browser/loader/resource_dispatcher_host_impl.h
+++ b/content/browser/loader/resource_dispatcher_host_impl.h
@@ -25,6 +25,7 @@
 #include "base/time.h"
 #include "base/timer.h"
 #include "content/browser/download/download_resource_handler.h"
+#include "content/browser/loader/render_view_host_tracker.h"
 #include "content/browser/loader/resource_loader.h"
 #include "content/browser/loader/resource_loader_delegate.h"
 #include "content/browser/loader/resource_scheduler.h"
@@ -167,13 +168,15 @@ class CONTENT_EXPORT ResourceDispatcherHostImpl
                                         const std::string& mime_type,
                                         ResourceType::Type resource_type);
 
+  // Called when a RenderViewHost is created.
+  void OnRenderViewHostCreated(int child_id, int route_id);
+
+  // Called when a RenderViewHost is deleted.
+  void OnRenderViewHostDeleted(int child_id, int route_id);
+
   // Force cancels any pending requests for the given process.
   void CancelRequestsForProcess(int child_id);
 
-  // Force cancels any pending requests for the given route id.  This method
-  // acts like CancelRequestsForProcess when route_id is -1.
-  void CancelRequestsForRoute(int child_id, int route_id);
-
   void OnUserGesture(WebContentsImpl* contents);
 
   // Retrieves a net::URLRequest.  Must be called from the IO thread.
@@ -290,6 +293,10 @@ class CONTENT_EXPORT ResourceDispatcherHostImpl
   // Estimate how much heap space |request| will consume to run.
   static int CalculateApproximateMemoryCost(net::URLRequest* request);
 
+  // Force cancels any pending requests for the given route id.  This method
+  // acts like CancelRequestsForProcess when route_id is -1.
+  void CancelRequestsForRoute(int child_id, int route_id);
+
   // The list of all requests that we have pending. This list is not really
   // optimized, and assumes that we have relatively few requests pending at once
   // since some operations require brute-force searching of the list.
@@ -437,6 +444,8 @@ class CONTENT_EXPORT ResourceDispatcherHostImpl
 
   scoped_ptr<ResourceScheduler> scheduler_;
 
+  RenderViewHostTracker tracker_;  // Lives on UI thread.
+
   DISALLOW_COPY_AND_ASSIGN(ResourceDispatcherHostImpl);
 };