cc: Single-threaded impl-side painting for unit tests

cc/trees/layer_tree_host.h

 // 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.
 
 #ifndef CC_TREES_LAYER_TREE_HOST_H_
 #define CC_TREES_LAYER_TREE_HOST_H_
 
 #include <limits>
 #include <list>
 #include <set>
@@ skipping 282 matching lines @@
   // to unregister itself.
   void InsertSwapPromiseMonitor(SwapPromiseMonitor* monitor);
   void RemoveSwapPromiseMonitor(SwapPromiseMonitor* monitor);
 
   // Call this function when you expect there to be a swap buffer.
   // See swap_promise.h for how to use SwapPromise.
   void QueueSwapPromise(scoped_ptr<SwapPromise> swap_promise);
 
   void BreakSwapPromises(SwapPromise::DidNotSwapReason reason);
 
+  size_t num_queued_swap_promises() const { return swap_promise_list_.size(); }
+
  protected:
   LayerTreeHost(LayerTreeHostClient* client,
                 SharedBitmapManager* manager,
                 const LayerTreeSettings& settings);
   void InitializeThreaded(
       scoped_refptr<base::SingleThreadTaskRunner> main_task_runner,
       scoped_refptr<base::SingleThreadTaskRunner> impl_task_runner);
   void InitializeSingleThreaded(
       LayerTreeHostSingleThreadClient* single_thread_client,
       scoped_refptr<base::SingleThreadTaskRunner> main_task_runner);
@@ skipping 141 matching lines @@
 
   ScopedPtrVector<SwapPromise> swap_promise_list_;
   std::set<SwapPromiseMonitor*> swap_promise_monitor_;
 
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHost);
 };
 
 }  // namespace cc
 
 #endif  // CC_TREES_LAYER_TREE_HOST_H_