Touch event flag should control only DOM event firing.

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

Index: third_party/WebKit/Source/core/input/TouchEventManager.cpp
diff --git a/third_party/WebKit/Source/core/input/TouchEventManager.cpp b/third_party/WebKit/Source/core/input/TouchEventManager.cpp
index 8cbaab593786745703e2db82a91ca6fa5f5c0b07..d62bf2ec6078d31d78eaa2ee86bbea68137f1f02 100644
--- a/third_party/WebKit/Source/core/input/TouchEventManager.cpp
+++ b/third_party/WebKit/Source/core/input/TouchEventManager.cpp
@@ -19,6 +19,7 @@
 #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>
@@ -487,6 +488,9 @@ class CurrentEventHolder {
 WebInputEventResult TouchEventManager::handleTouchEvent(
     const PlatformTouchEvent& event,
     HeapVector<TouchInfo>& touchInfos) {
+  if (!RuntimeEnabledFeatures::touchAPIEnabled())
+    return WebInputEventResult::HandledSystem;

[mustaq, 2016/11/03 18:10:49]

Should be NotHandled instead, to let the upstream event handlers know that the
page didn't do anything with the event. Could be HandledSuppressed, depends on
how the return value is used.

+
   // Track the current event for the scope of this function.
   CurrentEventHolder holder(m_currentEvent, event.type());