Use LatencyInfoSwapPromise to track LatencyInfo through compositor

cc/base/latency_info_swap_promise.h

Index: cc/base/latency_info_swap_promise.h
diff --git a/cc/base/latency_info_swap_promise.h b/cc/base/latency_info_swap_promise.h
new file mode 100644
index 0000000000000000000000000000000000000000..1d4e20867f89567d0b134bacd1784da70cba4e0e
--- /dev/null
+++ b/cc/base/latency_info_swap_promise.h
@@ -0,0 +1,30 @@
+// Copyright 2013 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_BASE_LATENCY_INFO_SWAP_PROMISE_H_
+#define CC_BASE_LATENCY_INFO_SWAP_PROMISE_H_
+
+#include "base/compiler_specific.h"
+#include "cc/base/swap_promise.h"
+#include "ui/events/latency_info.h"
+
+namespace cc {
+
+class LatencyInfoSwapPromise : public SwapPromise {
+ public:
+  explicit LatencyInfoSwapPromise(const ui::LatencyInfo& latency_info);
+  virtual ~LatencyInfoSwapPromise();
+
+  virtual void DidSwap(CompositorFrameMetadata* metadata) OVERRIDE;
+  virtual void DidNotSwap(DidNotSwapReason reason) OVERRIDE;
+
+  const ui::LatencyInfo& GetLatencyInfo();

[danakj, 2013/11/27 20:11:42]

This is no longer used, remove it.

[Yufeng Shen (Slow to review), 2013/11/27 20:18:52]

Done.

+
+ private:
+  ui::LatencyInfo latency_;
+};
+
+}  // namespace cc
+
+#endif  // CC_BASE_LATENCY_INFO_SWAP_PROMISE_H_