Fix unbounded allocation of GL queries

cc/resources/texture_uploader.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/resources/texture_uploader.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "base/debug/trace_event.h"
@@ skipping 98 matching lines @@
 double TextureUploader::EstimatedTexturesPerSecond() {
   ProcessQueries();
 
   // Use the median as our estimate.
   std::multiset<double>::iterator median = textures_per_second_history_.begin();
   std::advance(median, textures_per_second_history_.size() / 2);
   return *median;
 }
 
 void TextureUploader::BeginQuery() {
+  // Check to see if any of the pending queries are free before allocating a
+  // new one. If this is not done, queries may be allocated without bound.
+  // http://crbug.com/398072
+  if (available_queries_.empty())
+    ProcessQueries();
+
   if (available_queries_.empty())
     available_queries_.push_back(Query::Create(gl_));
 
   available_queries_.front()->Begin();
 }
 
 void TextureUploader::EndQuery() {
   available_queries_.front()->End();
   pending_queries_.push_back(available_queries_.take_front());
   num_blocking_texture_uploads_++;
@@ skipping 195 matching lines @@
       textures_per_second_history_.erase(textures_per_second_history_.begin());
       textures_per_second_history_.erase(--textures_per_second_history_.end());
     }
     textures_per_second_history_.insert(textures_per_second);
 
     available_queries_.push_back(pending_queries_.take_front());
   }
 }
 
 }  // namespace cc