[cc] Plumb BeginFrameAcks through SurfaceManager to DisplayScheduler.

cc/test/test_begin_frame_ack_tracker.h

+// Copyright 2017 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_TEST_TEST_BEGIN_FRAME_ACK_TRACKER_H_
+#define CC_TEST_TEST_BEGIN_FRAME_ACK_TRACKER_H_
+
+#include "cc/output/begin_frame_args.h"
+#include "cc/surfaces/surface_observer.h"
+
+namespace cc {
+
+class TestBeginFrameAckTracker : public SurfaceObserver {

[sunnyps, 2017/05/25 20:49:13]

nit: Can we rename this to FakeSurfaceObserver and add the other functionality
that's needed for some tests like tracking damaged surfaces?

[Eric Seckler, 2017/05/26 10:57:52]

Done.

+ public:
+  const BeginFrameAck& last_ack() {
+    return last_ack_;
+  }
+
+ private:
+  // SurfaceObserver implementation:
+  void OnSurfaceDamaged(const SurfaceId& surface,
+                        const BeginFrameAck& ack,
+                        bool* changed) override;
+  void OnSurfaceCreated(const SurfaceInfo& surface_info) override {}
+  void OnSurfaceDiscarded(const SurfaceId& surface_id) override {}
+  void OnSurfaceDestroyed(const SurfaceId& surface_id) override {}
+  void OnSurfaceDamageExpected(const SurfaceId& surface_id,
+                               const BeginFrameArgs& args) override {}
+
+  BeginFrameAck last_ack_;
+};
+
+}  // namespace cc
+
+#endif  // CC_TEST_TEST_BEGIN_FRAME_ACK_TRACKER_H_