Re-enable passthrough touch event queue.

ui/events/blink/web_input_event_traits.cc

 // Copyright 2016 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 "ui/events/blink/web_input_event_traits.h"
 
 #include "base/logging.h"
 #include "base/strings/stringprintf.h"
 #include "third_party/WebKit/public/platform/WebGestureEvent.h"
 #include "third_party/WebKit/public/platform/WebKeyboardEvent.h"
@@ skipping 179 matching lines @@
   Apply(WebInputEventSize(), type, type, &size);
   return size;
 }
 
 WebScopedInputEvent WebInputEventTraits::Clone(const WebInputEvent& event) {
   WebScopedInputEvent scoped_event;
   Apply(WebInputEventClone(), event.type(), event, &scoped_event);
   return scoped_event;
 }
 
-bool WebInputEventTraits::ShouldBlockEventStream(const WebInputEvent& event) {
+bool WebInputEventTraits::ShouldBlockEventStream(
+    const WebInputEvent& event,
+    bool raf_aligned_touch_enabled) {
   switch (event.type()) {
     case WebInputEvent::MouseDown:
     case WebInputEvent::MouseUp:
     case WebInputEvent::MouseEnter:
     case WebInputEvent::MouseLeave:
     case WebInputEvent::ContextMenu:
     case WebInputEvent::GestureScrollBegin:
     case WebInputEvent::GestureScrollEnd:
     case WebInputEvent::GestureShowPress:
     case WebInputEvent::GestureTapUnconfirmed:
@@ skipping 10 matching lines @@
                 static_cast<const WebTouchEvent&>(event).dispatchType);
       return false;
 
     // Touch start and touch end indicate whether they are non-blocking
     // (aka uncancelable) on the event.
     case WebInputEvent::TouchStart:
     case WebInputEvent::TouchEnd:
       return static_cast<const WebTouchEvent&>(event).dispatchType ==
              WebInputEvent::Blocking;
 
-    // Touch move events may be non-blocking but are always explicitly
-    // acknowledge by the renderer so they block the event stream.
     case WebInputEvent::TouchMove:
+      // Non-blocking touch moves can be ack'd right away if raf_aligned
+      // touch is enabled.
+      if (raf_aligned_touch_enabled) {
+        return static_cast<const WebTouchEvent&>(event).dispatchType ==
+               WebInputEvent::Blocking;
+      }
+      // Touch move events may be non-blocking but are always explicitly
+      // acknowledge by the renderer so they block the event stream.
+      return true;
     default:
       return true;
   }
 }
 
 bool WebInputEventTraits::CanCauseScroll(
     const blink::WebMouseWheelEvent& event) {
 #if defined(USE_AURA)
   // Scroll events generated from the mouse wheel when the control key is held
   // don't trigger scrolling. Instead, they may cause zooming.
@@ skipping 20 matching lines @@
     source_event_type = SourceEventType::WHEEL;
   } else if (event.sourceDevice ==
              blink::WebGestureDevice::WebGestureDeviceTouchscreen) {
     source_event_type = SourceEventType::TOUCH;
   }
   LatencyInfo latency_info(source_event_type);
   return latency_info;
 }
 
 }  // namespace ui