Use LatencyInfoSwapPromise to track LatencyInfo through compositor

cc/base/swap_promise.h

 // 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_SWAP_PROMISE_H_
 #define CC_BASE_SWAP_PROMISE_H_
 
+#include "base/compiler_specific.h"
+#include "ui/events/latency_info.h"
+
 namespace cc {
 
 const unsigned int kMaxQueuedSwapPromiseNumber = 100;
 
 // When a change to the compositor's state/invalidation/whatever happens, a
 // Swap Promise can be inserted into LayerTreeHost/LayerTreeImpl, to track
 // whether the compositor's reply to the new state/invaliadtion/whatever is
 // completed in the compositor, i.e. the compositor knows it has been sent
 // to its output or not.
 //
 // If the new compositor state is sent to the output, SwapPromise::DidSwap()
 // will be called, and if the compositor fails to send its new state to the
 // output, SwapPromise::DidNotSwap() will be called.
 //
 // Client wishes to use SwapPromise should have a subclass that defines
 // the behavior of DidSwap() and DidNotSwap(). Notice that the promise can
 // be broken at either main or impl thread, e.g. commit fails on main thread,
 // new frame data has no actual damage so LayerTreeHostImpl::SwapBuffers()
 // bails out early on impl thread, so don't assume that DidSwap() and
 // DidNotSwap() are called at a particular thread. It is better to let the
 // subclass carry thread-safe member data and operate on that member data in
 // DidSwap() and DidNotSwap().
 class SwapPromise {
  public:
-  SwapPromise() {}
-  virtual ~SwapPromise() {}
+  enum SwapPromiseType {
+    SWAP_PROMISE_UNKNOWN,
+    SWAP_PROMISE_LATENCY_INFO,
+  };
 
   enum DidNotSwapReason {
     DID_NOT_SWAP_UNKNOWN,
     SWAP_FAILS,
     COMMIT_FAILS,
     SWAP_PROMISE_LIST_OVERFLOW,
   };
 
+  explicit SwapPromise(SwapPromiseType type);
+  virtual ~SwapPromise();
+
+  SwapPromiseType type();
+
   virtual void DidSwap() = 0;
   virtual void DidNotSwap(DidNotSwapReason reason) = 0;
+
+ protected:
+  SwapPromiseType type_;
+};
+
+class LatencyInfoSwapPromise : public SwapPromise {

[danakj, 2013/11/26 19:17:53]

one class per file please

[Yufeng Shen (Slow to review), 2013/11/27 20:05:33]

Done.

+ public:
+  explicit LatencyInfoSwapPromise(const ui::LatencyInfo& latency_info);
+  virtual ~LatencyInfoSwapPromise();
+
+  virtual void DidSwap() OVERRIDE;
+  virtual void DidNotSwap(DidNotSwapReason reason) OVERRIDE;
+
+  const ui::LatencyInfo& GetLatencyInfo();
+
+ private:
+  ui::LatencyInfo latency_;
 };
 
 }  // namespace cc
 
 #endif  // CC_BASE_SWAP_PROMISE_H_