Record size of scroller that user scrolls

cc/input/scroller_size.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_INPUT_SCROLLER_SIZE_H_
+#define CC_INPUT_SCROLLER_SIZE_H_
+
+namespace cc {
+
+// Use the two constants to add scroller size related UMA metrics.
+static const int kMaxScrollerSize = 200000;  // Approximately 400px * 500px
+static const int kBucketNum = 50;

[bokan, 2017/04/18 19:24:38]

This name needs to be more specific. I would also replace const with constexpr.

[yigu, 2017/04/19 20:53:05]

Done.

+
+}  // namespace cc
+
+#endif  // CC_INPUT_SCROLLER_SIZE_H_