Don't restart the hang renderer timeout on messages ack'd from the compositor thread.

content/common/input/input_event_ack_location.h

Index: content/common/input/input_event_ack_location.h
diff --git a/content/common/input/input_event_ack_location.h b/content/common/input/input_event_ack_location.h
new file mode 100644
index 0000000000000000000000000000000000000000..20235d1fffd01841d8ae6d17a2c430043d532092
--- /dev/null
+++ b/content/common/input/input_event_ack_location.h
@@ -0,0 +1,21 @@
+// Copyright (c) 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.
+
+#ifndef CONTENT_COMMON_INPUT_INPUT_EVENT_ACK_LOCATION_H_
+#define CONTENT_COMMON_INPUT_INPUT_EVENT_ACK_LOCATION_H_
+
+namespace content {
+
+// Describes the location of where the input event ACK was
+// generated to the browser from the renderer.
+enum class InputEventAckLocation {

[tdresser, 2016/11/04 18:35:54]

I'd prefer InputEventAckSource, as it makes it clear you're referring to where
the ack was generated, rather than where it currently is.

This comment is a bit confusing.

Where the ack was "generated to" the browser? What does that mean?

[dtapuska, 2016/11/04 20:14:16]

Done.

+  INPUT_EVENT_ACK_LOCATION_UNKNOWN,

[dcheng, 2016/11/04 18:24:49]

Nit: since this is an enum class, just omit the INPUT_EVENT_ACK_LOCATION_ prefix

[dtapuska, 2016/11/04 20:14:16]

Done.

+  INPUT_EVENT_ACK_LOCATION_COMPOSITOR_THREAD,
+  INPUT_EVENT_ACK_LOCATION_MAIN_THREAD,
+  INPUT_EVENT_ACK_LOCATION_MAX = INPUT_EVENT_ACK_LOCATION_MAIN_THREAD
+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_INPUT_INPUT_EVENT_ACK_LOCATION_H_