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

content/common/input/input_event_ack.cc

Index: content/common/input/input_event_ack.cc
diff --git a/content/common/input/input_event_ack.cc b/content/common/input/input_event_ack.cc
index c7af9f85d25479954818e8464968f1bb8edcb0cd..92cf5eaed0c905b17dd63d9e3f81f80b533821ff 100644
--- a/content/common/input/input_event_ack.cc
+++ b/content/common/input/input_event_ack.cc
@@ -9,37 +9,50 @@
 namespace content {
 
 InputEventAck::InputEventAck(
+    InputEventAckSource source,
     blink::WebInputEvent::Type type,
     InputEventAckState state,
     const ui::LatencyInfo& latency,
     std::unique_ptr<ui::DidOverscrollParams> overscroll,
     uint32_t unique_touch_event_id)
-    : type(type),
+    : source(source),
+      type(type),
       state(state),
       latency(latency),
       overscroll(std::move(overscroll)),
       unique_touch_event_id(unique_touch_event_id) {}
 
-InputEventAck::InputEventAck(blink::WebInputEvent::Type type,
+InputEventAck::InputEventAck(InputEventAckSource source,
+                             blink::WebInputEvent::Type type,
                              InputEventAckState state,
                              const ui::LatencyInfo& latency,
                              uint32_t unique_touch_event_id)
-    : InputEventAck(type, state, latency, nullptr, unique_touch_event_id) {}
-
-InputEventAck::InputEventAck(blink::WebInputEvent::Type type,
+    : InputEventAck(source,
+                    type,
+                    state,
+                    latency,
+                    nullptr,
+                    unique_touch_event_id) {}
+
+InputEventAck::InputEventAck(InputEventAckSource source,
+                             blink::WebInputEvent::Type type,
                              InputEventAckState state,
                              uint32_t unique_touch_event_id)
-    : InputEventAck(type, state, ui::LatencyInfo(), unique_touch_event_id) {}
-
-InputEventAck::InputEventAck(blink::WebInputEvent::Type type,
+    : InputEventAck(source,
+                    type,
+                    state,
+                    ui::LatencyInfo(),
+                    unique_touch_event_id) {}
+
+InputEventAck::InputEventAck(InputEventAckSource source,
+                             blink::WebInputEvent::Type type,
                              InputEventAckState state)
-    : InputEventAck(type, state, 0) {
-}
+    : InputEventAck(source, type, state, 0) {}
 
 InputEventAck::InputEventAck()
-    : InputEventAck(blink::WebInputEvent::Undefined,
-                    INPUT_EVENT_ACK_STATE_UNKNOWN) {
-}
+    : InputEventAck(InputEventAckSource::UNKNOWN,
+                    blink::WebInputEvent::Undefined,
+                    INPUT_EVENT_ACK_STATE_UNKNOWN) {}
 
 InputEventAck::~InputEventAck() {
 }