Plumb firing passive event listeners.

content/renderer/input/render_widget_input_handler.cc

Index: content/renderer/input/render_widget_input_handler.cc
diff --git a/content/renderer/input/render_widget_input_handler.cc b/content/renderer/input/render_widget_input_handler.cc
index d5d5255c02f9c864a383a94ca1745f640d47461b..238ad5fe4e1efba35b24f8541a91607ed8814bbe 100644
--- a/content/renderer/input/render_widget_input_handler.cc
+++ b/content/renderer/input/render_widget_input_handler.cc
@@ -191,9 +191,8 @@ RenderWidgetInputHandler::~RenderWidgetInputHandler() {}
 
 void RenderWidgetInputHandler::HandleInputEvent(
     const WebInputEvent& input_event,
-    const ui::LatencyInfo& latency_info) {
-  // TODO(dtapuska): Passive support not implemented yet crbug.com/489802
-  bool passive = false;
+    const ui::LatencyInfo& latency_info,
+    bool passive) {
   base::AutoReset<bool> handling_input_event_resetter(&handling_input_event_,
                                                       true);
   base::AutoReset<WebInputEvent::Type> handling_event_type_resetter(
@@ -356,11 +355,15 @@ void RenderWidgetInputHandler::HandleInputEvent(
   // Send mouse wheel events and their disposition to the compositor thread, so
   // that they can be used to produce the elastic overscroll effect on Mac.
   if (input_event.type == WebInputEvent::MouseWheel) {
-    delegate_->ObserveWheelEventAndResult(
-        static_cast<const WebMouseWheelEvent&>(input_event),
-        event_overscroll ? event_overscroll->latest_overscroll_delta
-                         : gfx::Vector2dF(),
-        processed != WebInputEventResult::NotHandled);
+    const WebMouseWheelEvent& wheel_event =
+        static_cast<const WebMouseWheelEvent&>(input_event);
+    if (wheel_event.canScroll) {

[tdresser, 2016/01/26 16:34:37]

The canScroll check is unrelated to the rest of your patch, right?

[dtapuska, 2016/01/26 16:53:15]

Ultimately yes; for passive wheel listeners; canScroll is always false; but it
was taking this code path which actually is unintended.

[tdresser, 2016/01/26 18:45:42]

Acknowledged.

+      delegate_->ObserveWheelEventAndResult(
+          wheel_event,
+          event_overscroll ? event_overscroll->latest_overscroll_delta
+                           : gfx::Vector2dF(),
+          processed != WebInputEventResult::NotHandled);
+    }
   }
 
   bool frame_pending =
@@ -384,7 +387,12 @@ void RenderWidgetInputHandler::HandleInputEvent(
   // by reentrant calls for events after the paused one.
   bool no_ack = ignore_ack_for_mouse_move_from_debugger_ &&
                 input_event.type == WebInputEvent::MouseMove;
-  if (WebInputEventTraits::WillReceiveAckFromRenderer(input_event) && !no_ack) {
+  if (passive) {
+    // Passive means it was ack'd already by the InputHandlerProxy
+    // so let the delegate know the passive event has been handled.
+    delegate_->PassiveInputEventHandled(input_event.type);
+  } else if (WebInputEventTraits::WillReceiveAckFromRenderer(input_event) &&
+             !no_ack) {

[tdresser, 2016/01/26 16:34:37]

Is this indentation correct?

[dtapuska, 2016/01/26 16:53:15]

Done.

     scoped_ptr<InputEventAck> response(new InputEventAck(
         input_event.type, ack_result, swap_latency_info,
         std::move(event_overscroll),