Reserve space in the resource ID set.

cc/layers/delegated_renderer_layer_impl.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/layers/delegated_renderer_layer_impl.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 104 matching lines @@
     const ResourceProvider::ResourceIdMap& resource_map =
         resource_provider->GetChildToParentMap(child_id_);
 
   resource_provider->ReceiveFromChild(child_id_, frame_data->resource_list);
 
   RenderPassList render_pass_list;
   RenderPass::CopyAll(frame_data->render_pass_list, &render_pass_list);
 
   bool invalid_frame = false;
   ResourceProvider::ResourceIdSet resources_in_frame;
+  size_t reserve_size = frame_data->resource_list.size();
+#if defined(COMPILER_MSVC)
+  resources_in_frame.reserve(reserve_size);
+#elif defined(COMPILER_GCC)
+  // Pre-standard hash-tables only implement resize, which behaves similarly
+  // to reserve for these keys. Resizing to 0 may also be broken (particularly
+  // on stlport).
+  // TODO(jbauman): Replace with reserve when C++11 is supported everywhere.
+  if (reserve_size)
+    resources_in_frame.resize(reserve_size);
+#endif
   DrawQuad::ResourceIteratorCallback remap_resources_to_parent_callback =
       base::Bind(&ResourceRemapHelper,
                  &invalid_frame,
                  resource_map,
                  &resources_in_frame);
   for (const auto& pass : render_pass_list) {
     for (const auto& quad : pass->quad_list)
       quad->IterateResources(remap_resources_to_parent_callback);
   }
 
@@ skipping 390 matching lines @@
   if (own_child_id_) {
     ResourceProvider* provider = layer_tree_impl()->resource_provider();
     provider->DestroyChild(child_id_);
   }
 
   resources_.clear();
   child_id_ = 0;
 }
 
 }  // namespace cc