cc: Add CopyResource function to ResourceProvider API.

cc/resources/resource_pool.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/resources/resource_pool.h"
 
 #include "cc/resources/resource_provider.h"
 #include "cc/resources/scoped_resource.h"
 
 namespace cc {
@@ skipping 33 matching lines @@
     DCHECK(resource_provider_->CanLockForWrite(resource->id()));
 
     if (resource->size() != size)
       continue;
 
     unused_resources_.erase(it);
     unused_memory_usage_bytes_ -= resource->bytes();
     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();
 }
 
 void ResourcePool::ReleaseResource(scoped_ptr<ScopedResource> resource) {
   busy_resources_.push_back(resource.release());
 }
 
 void ResourcePool::SetResourceUsageLimits(size_t max_memory_usage_bytes,
@@ skipping 51 matching lines @@
     }
   }
 }
 
 void ResourcePool::DidFinishUsingResource(ScopedResource* resource) {
   unused_memory_usage_bytes_ += resource->bytes();
   unused_resources_.push_back(resource);
 }
 
 }  // namespace cc