cc: Remove some DCHECKs in CopyOutputRequest code.

cc/layers/layer_impl.cc

 // Copyright 2011 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/layers/layer_impl.h"
 
 #include "base/debug/trace_event.h"
 #include "base/strings/stringprintf.h"
 #include "cc/animation/animation_registrar.h"
 #include "cc/animation/scrollbar_animation_controller.h"
@@ skipping 90 matching lines @@
     return;
 
   children_.clear();
   layer_tree_impl()->set_needs_update_draw_properties();
 }
 
 void LayerImpl::PassCopyRequests(ScopedPtrVector<CopyOutputRequest>* requests) {
   if (requests->empty())
     return;
 
-  DCHECK(copy_requests_.empty());
-
   copy_requests_.insert_and_take(copy_requests_.end(), *requests);
   requests->clear();
 
   if (layer_tree_impl()->IsActiveTree())
     layer_tree_impl()->AddLayerWithCopyOutputRequest(this);
   NoteLayerPropertyChangedForSubtree();
 }
 
 void LayerImpl::TakeCopyRequestsAndTransformToTarget(
     ScopedPtrVector<CopyOutputRequest>* requests) {
@@ skipping 998 matching lines @@
 
 size_t LayerImpl::GPUMemoryUsageInBytes() const { return 0; }
 
 scoped_ptr<base::Value> LayerImpl::AsValue() const {
   scoped_ptr<base::DictionaryValue> state(new base::DictionaryValue());
   AsValueInto(state.get());
   return state.PassAs<base::Value>();
 }
 
 }  // namespace cc