cc: Keep track of busy resources in ResourcePool

cc/resources/resource_pool.h

Index: cc/resources/resource_pool.h
diff --git a/cc/resources/resource_pool.h b/cc/resources/resource_pool.h
index 21bbb0a70d072432048b2a75c2d925d461f81448..ef036420a4cea055401ed80b3520fc5976d0252f 100644
--- a/cc/resources/resource_pool.h
+++ b/cc/resources/resource_pool.h
@@ -12,10 +12,11 @@
 #include "cc/output/renderer.h"
 #include "cc/resources/resource.h"
 #include "cc/resources/resource_format.h"
+#include "cc/resources/resource_provider.h"
 
 namespace cc {
 
-class CC_EXPORT ResourcePool {
+class CC_EXPORT ResourcePool : public ResourceProviderClient {
  public:
   class CC_EXPORT Resource : public cc::Resource {
    public:
@@ -56,13 +57,17 @@ class CC_EXPORT ResourcePool {
     return resource_count_ - unused_resources_.size();
   }
 
+  // ResourceProviderClient implementation
+  virtual void ResourceExported(ResourceProvider::ResourceId id) OVERRIDE;
+  virtual void ResourceReturned(ResourceProvider::ResourceId id) OVERRIDE;
+
  protected:
   explicit ResourcePool(ResourceProvider* resource_provider);
 
   bool ResourceUsageTooHigh();
 
  private:
-  ResourceProvider* resource_provider_;
+  base::WeakPtr<ResourceProvider> resource_provider_;
   size_t max_memory_usage_bytes_;
   size_t max_unused_memory_usage_bytes_;
   size_t max_resource_count_;
@@ -72,6 +77,7 @@ class CC_EXPORT ResourcePool {
 
   typedef std::list<Resource*> ResourceList;
   ResourceList unused_resources_;
+  ResourceList exported_resources_;
 
   DISALLOW_COPY_AND_ASSIGN(ResourcePool);
 };