Stricter user gestures for touch - measure and warn

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 32 matching lines @@
 #include "core/events/DragEvent.h"
 #include "core/events/EventPath.h"
 #include "core/events/GestureEvent.h"
 #include "core/events/KeyboardEvent.h"
 #include "core/events/MouseEvent.h"
 #include "core/events/PointerEvent.h"
 #include "core/events/TextEvent.h"
 #include "core/events/TouchEvent.h"
 #include "core/events/WheelEvent.h"
 #include "core/fetch/ImageResource.h"
+#include "core/frame/Deprecation.h"
 #include "core/frame/EventHandlerRegistry.h"
 #include "core/frame/FrameHost.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
+#include "core/frame/UseCounter.h"
 #include "core/frame/VisualViewport.h"
 #include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLDialogElement.h"
 #include "core/html/HTMLFrameElementBase.h"
 #include "core/html/HTMLFrameSetElement.h"
 #include "core/html/HTMLInputElement.h"
 #include "core/input/InputDeviceCapabilities.h"
 #include "core/input/TouchActionUtil.h"
 #include "core/layout/HitTestRequest.h"
 #include "core/layout/HitTestResult.h"
@@ skipping 912 matching lines @@
 
     // For 4th/5th button in the mouse since Chrome does not yet send
     // button value to Blink but in some cases it does send the event.
     // This check is needed to suppress such an event (crbug.com/574959)
     if (mouseEvent.button() == NoButton)
         return WebInputEventResult::HandledSuppressed;
 
     RawPtr<FrameView> protector(m_frame->view());
 
     UserGestureIndicator gestureIndicator(DefinitelyProcessingUserGesture);
-    m_frame->localFrameRoot()->eventHandler().m_lastMouseDownUserGestureToken = gestureIndicator.currentToken();
+    m_frame->localFrameRoot()->eventHandler().m_lastMouseDownUserGestureToken = UserGestureIndicator::currentToken();
 
     cancelFakeMouseMoveEvent();
     if (m_eventHandlerWillResetCapturingMouseEventsNode)
         m_capturingMouseEventsNode = nullptr;
     m_mousePressed = true;
     m_capturesDragging = true;
     setLastKnownMousePosition(mouseEvent);
     m_mouseDownTimestamp = mouseEvent.timestamp();
     m_mouseDownMayStartDrag = false;
     selectionController().setMouseDownMayStartSelect(false);
@@ skipping 2751 matching lines @@
     if (freshTouchEvents) {
         // Ideally we'd ASSERT !m_touchSequenceDocument here since we should
         // have cleared the active document when we saw the last release. But we
         // have some tests that violate this, ClusterFuzz could trigger it, and
         // there may be cases where the browser doesn't reliably release all
         // touches. http://crbug.com/345372 tracks this.
         m_touchSequenceDocument.clear();
         m_touchSequenceUserGestureToken.clear();
     }
 
-    OwnPtr<UserGestureIndicator> gestureIndicator;
-
-    if (m_touchSequenceUserGestureToken)
-        gestureIndicator = adoptPtr(new UserGestureIndicator(m_touchSequenceUserGestureToken.release()));
-    else
-        gestureIndicator = adoptPtr(new UserGestureIndicator(DefinitelyProcessingUserGesture));
-
-    m_touchSequenceUserGestureToken = gestureIndicator->currentToken();
-
     ASSERT(m_frame->view());
     if (m_touchSequenceDocument && (!m_touchSequenceDocument->frame() || !m_touchSequenceDocument->frame()->view())) {
         // If the active touch document has no frame or view, it's probably being destroyed
         // so we can't dispatch events.
         return WebInputEventResult::NotHandled;
     }
 
     // First do hit tests for any new touch points.
     for (unsigned i = 0; i < points.size(); ++i) {
         const PlatformTouchPoint& point = points[i];
@@ skipping 57 matching lines @@
     // document set to receive the events, then we can skip all the rest of
     // this work.
     if (!m_touchSequenceDocument || !m_touchSequenceDocument->frameHost() || !hasTouchHandlers(m_touchSequenceDocument->frameHost()->eventHandlerRegistry()) || !m_touchSequenceDocument->frame()) {
         if (allTouchReleased) {
             m_touchSequenceDocument.clear();
             m_touchSequenceUserGestureToken.clear();
         }
         return WebInputEventResult::NotHandled;
     }
 
+    // Whether a touch should be considered a "user gesture" or not is a tricky question.
+    // https://docs.google.com/document/d/1oF1T3O7_E4t1PYHV6gyCwHxOi3ystm0eSL5xZu7nvOg/edit#
+    // TODO(rbyers): Disable user gesture in some cases but retain logging for now (crbug.com/582140).
+    OwnPtr<UserGestureIndicator> gestureIndicator;
+    if (event.touchPoints().size() == 1
+        && event.touchPoints()[0].state() == PlatformTouchPoint::TouchReleased
+        && !event.causesScrollingIfUncanceled()) {
+        // This is a touchend corresponding to a tap, definitely a user gesture.

[dtapuska, 2016/04/06 16:26:57]

I think this might need a comment that the callback is explicitly not set as to
avoid reporting UMA metrics in this code path.

+        gestureIndicator = adoptPtr(new UserGestureIndicator(DefinitelyProcessingUserGesture));
+    } else {
+        // This is some other touch event that perhaps shouldn't be considered a user gesture.
+        if (m_touchSequenceUserGestureToken)
+            gestureIndicator = adoptPtr(new UserGestureIndicator(m_touchSequenceUserGestureToken.release(), &m_touchSequenceDocument->frame()->eventHandler()));
+        else
+            gestureIndicator = adoptPtr(new UserGestureIndicator(DefinitelyProcessingUserGesture, &m_touchSequenceDocument->frame()->eventHandler()));
+        m_touchSequenceUserGestureToken = UserGestureIndicator::currentToken();
+    }
+
     // Compute and store the common info used by both PointerEvent and TouchEvent.
     HeapVector<TouchInfo> touchInfos(points.size());
 
     for (unsigned i = 0; i < points.size(); ++i) {
         const PlatformTouchPoint& point = points[i];
         PlatformTouchPoint::TouchState pointState = point.state();
         RawPtr<EventTarget> touchTarget = nullptr;
         String regionID;
 
         if (pointState == PlatformTouchPoint::TouchReleased || pointState == PlatformTouchPoint::TouchCancelled) {
@@ skipping 77 matching lines @@
             m_inPointerCanceledState = true;
             sendPointerCancels(touchInfos);
         }
     } else if (allTouchReleased) {
         m_inPointerCanceledState = false;
     }
 
     return eventResult;
 }
 
+void EventHandler::userGestureUsed()
+{
+    // This is invoked for UserGestureIndicators created in handleTouchEvent which perhaps represent
+    // touch actions which shouldn't be considered a user-gesture.
+    UseCounter::count(m_frame, UseCounter::TouchDragUserGestureUsed);
+    Deprecation::countDeprecationCrossOriginIframe(m_frame, UseCounter::TouchDragUserGestureUsedCrossOrigin);
+}
+
 void EventHandler::setLastKnownMousePosition(const PlatformMouseEvent& event)
 {
     m_mousePositionIsUnknown = false;
     m_lastKnownMousePosition = event.position();
     m_lastKnownMouseGlobalPosition = event.globalPosition();
 }
 
 WebInputEventResult EventHandler::passMousePressEventToSubframe(MouseEventWithHitTestResults& mev, LocalFrame* subframe)
 {
     selectionController().passMousePressEventToSubframe(mev);
@@ skipping 37 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