Non passive touch end or touch cancel listeners should not block scroll.

third_party/WebKit/Source/core/testing/Internals.idl

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  * Copyright (C) 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
@@ skipping 126 matching lines @@
 
     [RaisesException] long lastSpellCheckRequestSequence(Document document);
     [RaisesException] long lastSpellCheckProcessedSequence(Document document);
 
     sequence<DOMString> userPreferredLanguages();
     void setUserPreferredLanguages(sequence<DOMString> languages);
 
     unsigned long activeDOMObjectCount(Document document);
     unsigned long wheelEventHandlerCount(Document document);
     unsigned long scrollEventHandlerCount(Document document);
     unsigned long touchEventHandlerCount(Document document);

[Rick Byers, 2016/04/14 01:41:41]

nit: please rename this to make it clear it's only touchstart/move

Optionally while you're at it you could make both explicitly about "blocking"
(or change the impl to return a sum of passive+blocking).

[dtapuska, 2016/04/14 14:41:11]

Done.

+    unsigned long touchEndOrCancelEventHandlerCount(Document document);
     [RaisesException] LayerRectList touchEventTargetLayerRects(Document document);
 
     [RaisesException] boolean executeCommand(Document document, DOMString name, DOMString value);
 
     DOMString htmlNamespace();
     sequence<DOMString> htmlTags();
     DOMString svgNamespace();
     sequence<DOMString> svgTags();
 
     [RaisesException] NodeList nodesFromRect(Document document, long x, long y,
@@ skipping 196 matching lines @@
 
     void setMediaElementNetworkState(HTMLMediaElement element, long state);
 
     // TODO(liberato): remove once autoplay gesture override experiment concludes.
     void triggerAutoplayViewportCheck(HTMLMediaElement mediaElement);
 
     DOMString getScrollAnimationState(Node node);
 
     DOMString getProgrammaticScrollAnimationState(Node node);
 };