Add SwapPromise support to LayerTreeHost and LayerTreeImpl

cc/trees/layer_tree_host.h

Index: cc/trees/layer_tree_host.h
diff --git a/cc/trees/layer_tree_host.h b/cc/trees/layer_tree_host.h
index 339ae4e3e0d62e635aa9bc02239ab8213d23320e..6f7bdcbc02cc236c14970516eff59a34ee28d928 100644
--- a/cc/trees/layer_tree_host.h
+++ b/cc/trees/layer_tree_host.h
@@ -15,12 +15,14 @@
 #include "base/containers/hash_tables.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/memory/scoped_vector.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "base/timer/timer.h"
 #include "cc/animation/animation_events.h"
 #include "cc/base/cc_export.h"
 #include "cc/base/scoped_ptr_vector.h"
+#include "cc/base/swap_promise.h"
 #include "cc/debug/micro_benchmark.h"
 #include "cc/debug/micro_benchmark_controller.h"
 #include "cc/input/input_handler.h"
@@ -286,6 +288,15 @@ class CC_EXPORT LayerTreeHost {
                               scoped_ptr<base::Value> value,
                               const MicroBenchmark::DoneCallback& callback);
 
+  // Call this function when you expect there to be a swap buffer.
+  // See swap_promise.h for how to use SwapPromise.
+  // LTH will take the ownership of |swap_promise|.

[danakj, 2013/11/13 23:22:09]

Spell out LayerTreeHost.

[Yufeng Shen (Slow to review), 2013/11/14 22:09:55]

Done.

+  void QueueSwapPromise(SwapPromise* swap_promise);

[danakj, 2013/11/13 23:22:09]

If ownership passes, why is this a raw pointer and not a scoped_ptr?

[Yufeng Shen (Slow to review), 2013/11/14 22:09:55]

Done.

+
+  bool HasQueuedSwapPromise();
+  void FinishSwapPromise();
+  void BreakSwapPromise(SwapPromise::DidNotSwapReason reason);
+
  protected:
   LayerTreeHost(LayerTreeHostClient* client,
                 SharedBitmapManager* manager,
@@ -433,6 +444,8 @@ class CC_EXPORT LayerTreeHost {
 
   SharedBitmapManager* shared_bitmap_manager_;
 
+  ScopedVector<SwapPromise> swap_promise_list_;

[danakj, 2013/11/13 23:22:09]

ScopedPtrVector?

[Yufeng Shen (Slow to review), 2013/11/14 22:09:55]

Done.

+
   DISALLOW_COPY_AND_ASSIGN(LayerTreeHost);
 };