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

content/browser/renderer_host/render_widget_host_view_mac_unittest.mm

Index: content/browser/renderer_host/render_widget_host_view_mac_unittest.mm
diff --git a/content/browser/renderer_host/render_widget_host_view_mac_unittest.mm b/content/browser/renderer_host/render_widget_host_view_mac_unittest.mm
index e08e33974e2a658132ea310202f8630514bbfb22..d98d707a1bd1e27694fc78650efa524911a27a4d 100644
--- a/content/browser/renderer_host/render_widget_host_view_mac_unittest.mm
+++ b/content/browser/renderer_host/render_widget_host_view_mac_unittest.mm
@@ -954,7 +954,8 @@ TEST_F(RenderWidgetHostViewMacTest, ScrollWheelEndEventDelivery) {
   process_host->sink().ClearMessages();
 
   // Send an ACK for the first wheel event, so that the queue will be flushed.
-  InputEventAck ack(blink::WebInputEvent::MouseWheel,
+  InputEventAck ack(InputEventAckSource::COMPOSITOR_THREAD,
+                    blink::WebInputEvent::MouseWheel,
                     INPUT_EVENT_ACK_STATE_CONSUMED);
   std::unique_ptr<IPC::Message> response(
       new InputHostMsg_HandleInputEvent_ACK(0, ack));
@@ -999,7 +1000,8 @@ TEST_F(RenderWidgetHostViewMacTest,
   process_host->sink().ClearMessages();
 
   // Indicate that the wheel event was unhandled.
-  InputEventAck unhandled_ack(blink::WebInputEvent::MouseWheel,
+  InputEventAck unhandled_ack(InputEventAckSource::COMPOSITOR_THREAD,
+                              blink::WebInputEvent::MouseWheel,
                               INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
   std::unique_ptr<IPC::Message> response1(
       new InputHostMsg_HandleInputEvent_ACK(0, unhandled_ack));
@@ -1007,7 +1009,8 @@ TEST_F(RenderWidgetHostViewMacTest,
   ASSERT_EQ(2U, process_host->sink().message_count());
   process_host->sink().ClearMessages();
 
-  InputEventAck unhandled_scroll_ack(blink::WebInputEvent::GestureScrollUpdate,
+  InputEventAck unhandled_scroll_ack(InputEventAckSource::COMPOSITOR_THREAD,
+                                     blink::WebInputEvent::GestureScrollUpdate,
                                      INPUT_EVENT_ACK_STATE_NOT_CONSUMED);
   std::unique_ptr<IPC::Message> scroll_response1(
       new InputHostMsg_HandleInputEvent_ACK(0, unhandled_scroll_ack));
@@ -1168,7 +1171,8 @@ TEST_F(RenderWidgetHostViewMacPinchTest, PinchThresholding) {
   process_host_->sink().ClearMessages();
 
   // We'll use this IPC message to ack events.
-  InputEventAck ack(blink::WebInputEvent::GesturePinchUpdate,
+  InputEventAck ack(InputEventAckSource::COMPOSITOR_THREAD,
+                    blink::WebInputEvent::GesturePinchUpdate,
                     INPUT_EVENT_ACK_STATE_CONSUMED);
   std::unique_ptr<IPC::Message> response(
       new InputHostMsg_HandleInputEvent_ACK(0, ack));