cc: Add CopyResource function to ResourceProvider API.

cc/resources/resource_pool.cc

Index: cc/resources/resource_pool.cc
diff --git a/cc/resources/resource_pool.cc b/cc/resources/resource_pool.cc
index 7170a397c7086016dbca69d0bfcf8341f0898b5d..31b9b272013989ced09e369921056b3d988da66b 100644
--- a/cc/resources/resource_pool.cc
+++ b/cc/resources/resource_pool.cc
@@ -51,16 +51,10 @@ scoped_ptr<ScopedResource> ResourcePool::AcquireResource(
     return make_scoped_ptr(resource);
   }
 
-  // Create new resource.
   scoped_ptr<ScopedResource> resource =
       ScopedResource::Create(resource_provider_);
   resource->AllocateManaged(size, target_, format_);
 
-  // Extend all read locks on all resources until the resource is
-  // finished being used, such that we know when resources are
-  // truly safe to recycle.
-  resource_provider_->EnableReadLockFences(resource->id(), true);
-
   memory_usage_bytes_ += resource->bytes();
   ++resource_count_;
   return resource.Pass();