Tiimer based phase info generated for mouse wheel events.

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 202 matching lines @@
     case WebInputEvent::kTouchMove:
       // 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).dispatch_type ==
                WebInputEvent::kBlocking;
       }
       // Touch move events may be non-blocking but are always explicitly
       // acknowledge by the renderer so they block the event stream.
       return true;
+
+    case WebInputEvent::kMouseWheel:
+      return static_cast<const WebMouseWheelEvent&>(event).dispatch_type ==

[bokan, 2017/05/18 16:47:01]

How is this related to this change?

[sahel, 2017/05/18 18:15:15]

When a GSB with touch source arrives, we should stop the current wheel based
scrolling sequence. To implement this, we stop the timer and send a synthetic
wheel event with dispatch type nonblocking to send early ack. This is because we
don't want to generate the GSE with touchpad source after GSB with touchscreen
source.

+             WebInputEvent::kBlocking;
+
     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 21 matching lines @@
     source_event_type = SourceEventType::WHEEL;
   } else if (event.source_device ==
              blink::WebGestureDevice::kWebGestureDeviceTouchscreen) {
     source_event_type = SourceEventType::TOUCH;
   }
   LatencyInfo latency_info(source_event_type);
   return latency_info;
 }
 
 }  // namespace ui