Add UMA metric for tracking listeners for blocking touch before page finished loading

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

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  *
  * 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 238 matching lines @@
         FrameView* view = document->view();
         if (view && view->isScrollable())
             result += kTouchTargetHistogramScrollableDocumentOffset;
     }
 
     if (dispatchResult != DispatchEventResult::NotCanceled)
         result += kTouchTargetHistogramHandledOffset;
     return static_cast<TouchTargetAndDispatchResultType>(result);
 }
 
+enum TouchEventDispatchResultType {
+    NotHandledTouches, // Not handled touch events.

[Ilya Sherman, 2016/04/26 20:27:11]

"Not handled events" -- does that mean "Unhandled events"?  Or "no (zero)
handled events"?  I'm finding this phrasing somewhat confusing.

[lanwei, 2016/04/27 04:43:30]

Done.

+    HandledTouches, // Handled touch events.
+    TouchEventDispatchResultTypeMax,
+};
+
 } // namespace
 
 using namespace HTMLNames;
 
 // The link drag hysteresis is much larger than the others because there
 // needs to be enough space to cancel the link press without starting a link drag,
 // and because dragging links is rare.
 static const int LinkDragHysteresis = 40;
 static const int ImageDragHysteresis = 5;
 static const int TextDragHysteresis = 3;
@@ skipping 3617 matching lines @@
                 eventName, touchEventTarget->toNode()->document().domWindow(),
                 event.getModifiers(), event.cancelable(), event.causesScrollingIfUncanceled(), event.timestamp());
 
             DispatchEventResult domDispatchResult = touchEventTarget->dispatchEvent(touchEvent);
 
             // Only report for top level documents with a single touch on
             // touch-start or the first touch-move.
             if (touchStartOrFirstTouchMove && touchInfos.size() == 1 && event.cancelable() && !m_frame->document()->ownerElement()) {
                 DEFINE_STATIC_LOCAL(EnumerationHistogram, rootDocumentListenerHistogram, ("Event.Touch.TargetAndDispatchResult", TouchTargetAndDispatchResultTypeMax));
                 rootDocumentListenerHistogram.count(toTouchTargetHistogramValue(eventTarget, domDispatchResult));
+
+                // Count the canceled touch starts and first touch moves before and after page finishes loading respectively.
+                if (m_frame->document()->isLoadCompleted()) {
+                    DEFINE_STATIC_LOCAL(EnumerationHistogram, touchesCanceledAfterPageLoadHistogram, ("Event.Touch.TouchesCanceledAfterPageLoad", TouchEventDispatchResultTypeMax));
+                    touchesCanceledAfterPageLoadHistogram.count((domDispatchResult != DispatchEventResult::NotCanceled) ? HandledTouches : NotHandledTouches);
+                } else {
+                    DEFINE_STATIC_LOCAL(EnumerationHistogram, touchesCanceledBeforePageLoadHistogram, ("Event.Touch.TouchesCanceledBeforePageLoad", TouchEventDispatchResultTypeMax));
+                    touchesCanceledBeforePageLoadHistogram.count((domDispatchResult != DispatchEventResult::NotCanceled) ? HandledTouches : NotHandledTouches);
+                }
             }
             eventResult = mergeEventResult(eventResult, toWebInputEventResult(domDispatchResult));
         }
     }
-
     return eventResult;
 }
 
 WebInputEventResult EventHandler::handleTouchEvent(const PlatformTouchEvent& event)
 {
     TRACE_EVENT0("blink", "EventHandler::handleTouchEvent");
 
     if (event.type() == PlatformEvent::TouchScrollStarted) {
         m_pointerEventManager.blockTouchPointers();
         return WebInputEventResult::HandledSystem;
@@ skipping 259 matching lines @@
 PlatformEvent::Modifiers EventHandler::accessKeyModifiers()
 {
 #if OS(MACOSX)
     return static_cast<PlatformEvent::Modifiers>(PlatformEvent::CtrlKey | PlatformEvent::AltKey);
 #else
     return PlatformEvent::AltKey;
 #endif
 }
 
 } // namespace blink