Always make context current in ViewManager's BitmapUploader, be laxer in SurfaceResourceHolder

cc/surfaces/surface_resource_holder.cc

 // Copyright 2014 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/surfaces/surface_resource_holder.h"
 
 #include "cc/surfaces/surface_factory_client.h"
 
 namespace cc {
 
@@ skipping 33 matching lines @@
 
 void SurfaceResourceHolder::UnrefResources(
     const ReturnedResourceArray& resources) {
   ReturnedResourceArray resources_available_to_return;
 
   for (ReturnedResourceArray::const_iterator it = resources.begin();
        it != resources.end();
        ++it) {
     ResourceProvider::ResourceId id = it->id;
     ResourceIdCountMap::iterator count_it = resource_id_use_count_map_.find(id);
-    DCHECK(count_it != resource_id_use_count_map_.end());
+    if (count_it == resource_id_use_count_map_.end())
+      continue;
     ResourceRefs& ref = count_it->second;
     ref.refs_holding_resource_alive -= it->count;
     if (ref.refs_holding_resource_alive == 0) {
       ReturnedResource returned = *it;
       returned.count = ref.refs_received_from_child;
       resources_available_to_return.push_back(returned);
       resource_id_use_count_map_.erase(count_it);
     }
   }
 
   client_->ReturnResources(resources_available_to_return);
 }
 
 }  // namespace cc