[DevTools] Send ack early when paused in mouse move to keep events coming.

content/renderer/render_widget.cc

Index: content/renderer/render_widget.cc
diff --git a/content/renderer/render_widget.cc b/content/renderer/render_widget.cc
index 3a39f6040cfd57f53cf3290bbbebabee32a87c69..ccbde89452945af158ae8f965ea7833bec2a7189 100644
--- a/content/renderer/render_widget.cc
+++ b/content/renderer/render_widget.cc
@@ -373,7 +373,8 @@ RenderWidget::RenderWidget(blink::WebPopupType popup_type,
       has_focus_(false),
       handling_input_event_(false),
       handling_ime_event_(false),
-      handling_touchstart_event_(false),
+      handling_event_type_(WebInputEvent::Undefined),
+      ignore_ack_for_current_mouse_move_(false),
       closing_(false),
       is_swapped_out_(swapped_out),
       input_method_is_active_(false),
@@ -916,6 +917,7 @@ void RenderWidget::OnHandleInputEvent(const blink::WebInputEvent* input_event,
     handling_input_event_ = false;
     return;
   }
+  handling_event_type_ = input_event->type;
 
   base::TimeTicks start_time;
   if (base::TimeTicks::IsHighResNowFastAndReliable())
@@ -1001,9 +1003,6 @@ void RenderWidget::OnHandleInputEvent(const blink::WebInputEvent* input_event,
     prevent_default = prevent_default || WillHandleGestureEvent(gesture_event);
   }
 
-  if (input_event->type == WebInputEvent::TouchStart)
-      handling_touchstart_event_ = true;
-
   bool processed = prevent_default;
   if (input_event->type != WebInputEvent::Char || !suppress_next_char_events_) {
     suppress_next_char_events_ = false;
@@ -1011,8 +1010,6 @@ void RenderWidget::OnHandleInputEvent(const blink::WebInputEvent* input_event,
       processed = webwidget_->handleInputEvent(*input_event);
   }
 
-  handling_touchstart_event_ = false;
-
   // If this RawKeyDown event corresponds to a browser keyboard shortcut and
   // it's not processed by webkit, then we need to suppress the upcoming Char
   // events.
@@ -1061,7 +1058,11 @@ void RenderWidget::OnHandleInputEvent(const blink::WebInputEvent* input_event,
 
   TRACE_EVENT_SYNTHETIC_DELAY_END("blink.HandleInputEvent");
 
-  if (!WebInputEventTraits::IgnoresAckDisposition(*input_event)) {
+  // Note that we can't use handling_event_type_ here since it will be overriden
+  // by reentrant calls for events after the paused one.
+  bool no_ack = ignore_ack_for_current_mouse_move_ &&
+      input_event->type == WebInputEvent::MouseMove;
+  if (!WebInputEventTraits::IgnoresAckDisposition(*input_event) && !no_ack) {
     scoped_ptr<IPC::Message> response(
         new InputHostMsg_HandleInputEvent_ACK(routing_id_,
                                               input_event->type,
@@ -1087,6 +1088,7 @@ void RenderWidget::OnHandleInputEvent(const blink::WebInputEvent* input_event,
       Send(response.release());
     }
   }
+  ignore_ack_for_current_mouse_move_ = false;
 
 #if defined(OS_ANDROID)
   // Allow the IME to be shown when the focus changes as a consequence
@@ -1101,6 +1103,7 @@ void RenderWidget::OnHandleInputEvent(const blink::WebInputEvent* input_event,
     UpdateTextInputState(SHOW_IME_IF_NEEDED, FROM_IME);
 #endif
 
+  handling_event_type_ = WebInputEvent::Undefined;
   handling_input_event_ = false;
 
   if (!prevent_default) {
@@ -1541,6 +1544,21 @@ bool RenderWidget::ShouldHandleImeEvent() {
 #endif
 }
 
+bool RenderWidget::SendAckForCurrentMouseMove() {
+  if (handling_event_type_ == WebInputEvent::MouseMove) {
+    Send(new InputHostMsg_HandleInputEvent_ACK(routing_id_,
+                                               handling_event_type_,
+                                               INPUT_EVENT_ACK_STATE_CONSUMED,
+                                               ui::LatencyInfo()));
+    return true;
+  }
+  return false;
+}
+
+void RenderWidget::IgnoreAckForCurrentMouseMove() {
+  ignore_ack_for_current_mouse_move_ = true;
+}
+
 void RenderWidget::SetDeviceScaleFactor(float device_scale_factor) {
   if (device_scale_factor_ == device_scale_factor)
     return;
@@ -1992,7 +2010,7 @@ void RenderWidget::setTouchAction(
 
   // Ignore setTouchAction calls that result from synthetic touch events (eg.
   // when blink is emulating touch with mouse).
-  if (!handling_touchstart_event_)
+  if (!handling_event_type_ == WebInputEvent::TouchStart)
     return;
 
    // Verify the same values are used by the types so we can cast between them.