cc: Add frame timing request plumbing through the layers.

cc/debug/frame_timing_request.h

+// Copyright 2015 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_DEBUG_FRAME_TIMING_REQUEST_H_
+#define CC_DEBUG_FRAME_TIMING_REQUEST_H_
+
+#include "ui/gfx/geometry/rect.h"
+
+namespace cc {
+
+// This class represents a request from Blink to record frame timing information

[danakj, 2015/01/23 19:40:18]

nit: Mentioning Blink is a layering violation, but I'm not sure how to better
word this without it. If you can think of something that'd be good.

[vmpstr, 2015/01/23 21:01:13]

Done.

+// about the given rect (in layer space) and an associated request id. When
+// this request is propagated to the active LayerImpl, it will cause events to
+// be saved in FrameTimingTracker, which in turn will be consumed by Blink.
+class FrameTimingRequest {
+ public:
+  FrameTimingRequest();
+  FrameTimingRequest(int64_t request_id, const gfx::Rect& rect);
+
+  int64_t id() const { return id_; }
+  const gfx::Rect& rect() const { return rect_; }
+
+ private:
+  int64_t id_;
+  gfx::Rect rect_;
+};
+
+}  // namespace cc
+
+#endif  // CC_DEBUG_FRAME_TIMING_REQUEST_H_