Add InputEventTimestampSource interface.

remoting/protocol/input_event_timestamps.cc

Index: remoting/protocol/input_event_timestamps.cc
diff --git a/remoting/protocol/input_event_timestamps.cc b/remoting/protocol/input_event_timestamps.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b75e69f698ee36279d990caff8797b1edd8ebb21
--- /dev/null
+++ b/remoting/protocol/input_event_timestamps.cc
@@ -0,0 +1,25 @@
+// Copyright 2016 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.
+
+#include "remoting/protocol/input_event_timestamps.h"
+
+namespace remoting {
+namespace protocol {
+
+InputEventTimestampsSourceImpl::InputEventTimestampsSourceImpl() {}
+InputEventTimestampsSourceImpl::~InputEventTimestampsSourceImpl() {}
+
+void InputEventTimestampsSourceImpl::OnEventReceived(
+    InputEventTimestamps timestamps) {
+  last_timestamps_ = timestamps;
+}
+
+InputEventTimestamps InputEventTimestampsSourceImpl::TakeLastEventTimestamps() {
+  InputEventTimestamps result = last_timestamps_;
+  last_timestamps_ = InputEventTimestamps();
+  return result;
+}
+
+}  // namespace protocol
+}  // namespace remoting