Suppressed MEs for gestures from cancelled PEs

third_party/WebKit/Source/core/input/TouchEventManager.cpp

 // 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 "core/input/TouchEventManager.h"
 
 #include "core/dom/Document.h"
 #include "core/events/TouchEvent.h"
 #include "core/frame/Deprecation.h"
 #include "core/frame/EventHandlerRegistry.h"
@@ skipping 426 matching lines @@
 WebInputEventResult TouchEventManager::handleTouchEvent(
     const PlatformTouchEvent& event,
     HeapVector<TouchInfo>& touchInfos)
 {
     // Track the current event for the scope of this function.
     CurrentEventHolder holder(m_currentEvent, event.type());
 
     if (!reHitTestTouchPointsIfNeeded(event, touchInfos))
         return WebInputEventResult::NotHandled;
 
-    // Note that the disposition of any pointer events affects only the generation of touch
-    // events. If all pointer events were handled (and hence no touch events were fired), that
-    // is still equivalent to the touch events going unhandled because pointer event handler
-    // don't block scroll gesture generation.
-
-    // TODO(crbug.com/507408): If PE handlers always call preventDefault, we won't see TEs until after
-    // scrolling starts because the scrolling would suppress upcoming PEs. This sudden "break" in TE
-    // suppression can make the visible TEs inconsistent (e.g. touchmove without a touchstart).
-
     bool allTouchesReleased = true;
     for (const auto& point : event.touchPoints()) {
         if (point.state() != PlatformTouchPoint::TouchReleased
             && point.state() != PlatformTouchPoint::TouchCancelled)
             allTouchesReleased = false;
     }
 
     // Whether a touch should be considered a "user gesture" or not is a tricky question.
     // https://docs.google.com/document/d/1oF1T3O7_E4t1PYHV6gyCwHxOi3ystm0eSL5xZu7nvOg/edit#
 
@@ skipping 74 matching lines @@
         feature = UseCounter::TouchEndDuringScrollUserGestureUtilized;
         break;
     default:
         NOTREACHED();
         return;
     }
     Deprecation::countDeprecation(m_frame, feature);
 }
 
 } // namespace blink