Reset the default value of touch event flag back to "Auto".

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"
 #include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
 #include "core/html/HTMLCanvasElement.h"
 #include "core/input/EventHandlingUtil.h"
 #include "core/input/TouchActionUtil.h"
 #include "core/layout/HitTestCanvasResult.h"
 #include "core/page/ChromeClient.h"
 #include "core/page/Page.h"
 #include "platform/Histogram.h"
 #include "platform/PlatformTouchEvent.h"
-#include "platform/RuntimeEnabledFeatures.h"
 #include "wtf/CurrentTime.h"
 #include "wtf/PtrUtil.h"
 #include <memory>
 
 namespace blink {
 
 namespace {
 
 bool hasTouchHandlers(const EventHandlerRegistry& registry) {
   return registry.hasEventHandlers(
@@ skipping 451 matching lines @@
   }
   ~CurrentEventHolder() { m_target = PlatformEvent::NoType; }
 
  private:
   PlatformEvent::EventType& m_target;
 };
 
 WebInputEventResult TouchEventManager::handleTouchEvent(
     const PlatformTouchEvent& event,
     HeapVector<TouchInfo>& touchInfos) {
-  if (!RuntimeEnabledFeatures::touchEventAPIEnabled())
-    return WebInputEventResult::HandledSuppressed;
+  // We ideally want to suppress TouchEvent firing when touch detection is

[Rick Byers, 2016/12/01 21:40:16]

FWIW I don't agree with this comment.  We'd "ideally" send touch events all the
time AND enable TouchEvent feature detection all the time.  But the latter has
stupid web compat problems, so we can't do it.  But IMHO there's no good reason
not to do the former.

Perhaps we should rename (again, sorry) the feature from "touchEventAPIEnabled"
to "touchEventFeatureDetectionEnabled"?  Or for now just add a comment to
RuntimeEnabledFeatures.in saying that's really what it means (that "touch
events" themselves are always enabled since they're a feature always supported
by Chrome).

+  // disabled but we need to support dev-tools emulation and "some" dynamic
+  // cases.
 
   // Track the current event for the scope of this function.
   CurrentEventHolder holder(m_currentEvent, event.type());
 
   if (!reHitTestTouchPointsIfNeeded(event, touchInfos))
     return WebInputEventResult::NotHandled;
 
   bool allTouchesReleased = true;
   for (const auto& point : event.touchPoints()) {
     if (point.state() != PlatformTouchPoint::TouchReleased &&
         point.state() != PlatformTouchPoint::TouchCancelled)
       allTouchesReleased = false;
   }
 
   return dispatchTouchEvents(event, touchInfos, allTouchesReleased);
 }
 
 bool TouchEventManager::isAnyTouchActive() const {
   return m_touchPressed;
 }
 
 }  // namespace blink