Re-enable Eager Gesture Recognition on Aura

content/browser/renderer_host/render_widget_host_view_aura.cc

 // Copyright (c) 2012 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.
 
 #include "content/browser/renderer_host/render_widget_host_view_aura.h"
 
 #include "base/auto_reset.h"
 #include "base/basictypes.h"
 #include "base/bind.h"
 #include "base/callback_helpers.h"
@@ skipping 1145 matching lines @@
 }
 
 void RenderWidgetHostViewAura::ProcessAckedTouchEvent(
     const TouchEventWithLatencyInfo& touch, InputEventAckState ack_result) {
   ScopedVector<ui::TouchEvent> events;
   if (!MakeUITouchEventsFromWebTouchEvents(touch, &events,
                                            SCREEN_COORDINATES))
     return;
 
   aura::WindowTreeHost* host = window_->GetHost();
-  // |host| is NULL during tests.
+  // |host| may be null during tests.
   if (!host)
     return;
 
   ui::EventResult result = (ack_result ==
       INPUT_EVENT_ACK_STATE_CONSUMED) ? ui::ER_HANDLED : ui::ER_UNHANDLED;
   for (ScopedVector<ui::TouchEvent>::iterator iter = events.begin(),
       end = events.end(); iter != end; ++iter) {
     host->dispatcher()->ProcessedTouchEvent((*iter), window_, result);
   }
 }
@@ skipping 844 matching lines @@
 
   event->SetHandled();
 }
 
 void RenderWidgetHostViewAura::OnTouchEvent(ui::TouchEvent* event) {
   TRACE_EVENT0("input", "RenderWidgetHostViewAura::OnTouchEvent");
   if (touch_editing_client_ && touch_editing_client_->HandleInputEvent(event))
     return;
 
   // Update the touch event first.
-  blink::WebTouchPoint* point = UpdateWebTouchEventFromUIEvent(*event,
-                                                                &touch_event_);
+  blink::WebTouchPoint* point =
+      UpdateWebTouchEventFromUIEvent(*event, &touch_event_);
+
+  bool should_forward = host_->ShouldForwardTouchEvent();
 
   // Forward the touch event only if a touch point was updated, and there's a
   // touch-event handler in the page, and no other touch-event is in the queue.
   // It is important to always consume the event if there is a touch-event
   // handler in the page, or some touch-event is already in the queue, even if
   // no point has been updated, to make sure that this event does not get
   // processed by the gesture recognizer before the events in the queue.
-  if (host_->ShouldForwardTouchEvent())
+  if (point && should_forward) {
+    DCHECK(window_->GetHost());
+    if (window_->GetHost()->dispatcher()->OnForwardingAsyncTouchEvent(event))
+      host_->ForwardTouchEventWithLatencyInfo(touch_event_, *event->latency());
+  }
+
+  if (should_forward)
     event->StopPropagation();

[jdduke (slow), 2014/10/22 17:51:02]

Does it matter that the touch may have been ack'ed synchronously even if it was
forwarded? Will calling StopPropagation do the right thing in that case?

[tdresser, 2014/10/22 18:24:08]

In that case, we'll synchronously hit
WindowEventDispatcher::ProcessedTouchEvent, and turn the touch into a gesture
(if necessary), before the StopPropagation call occurs. 

I think its fine.

 
-  if (point) {
-    if (host_->ShouldForwardTouchEvent())
-      host_->ForwardTouchEventWithLatencyInfo(touch_event_, *event->latency());
+  if (point)
     UpdateWebTouchEventAfterDispatch(&touch_event_, point);
-  }
 }
 
 void RenderWidgetHostViewAura::OnGestureEvent(ui::GestureEvent* event) {
   TRACE_EVENT0("input", "RenderWidgetHostViewAura::OnGestureEvent");
   if ((event->type() == ui::ET_GESTURE_PINCH_BEGIN ||
       event->type() == ui::ET_GESTURE_PINCH_UPDATE ||
       event->type() == ui::ET_GESTURE_PINCH_END) && !pinch_zoom_enabled_) {
     event->SetHandled();
     return;
   }
@@ skipping 548 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // RenderWidgetHostViewBase, public:
 
 // static
 void RenderWidgetHostViewBase::GetDefaultScreenInfo(WebScreenInfo* results) {
   GetScreenInfoForWindow(results, NULL);
 }
 
 }  // namespace content