Suppress drag and drop on links on touch screen.

third_party/WebKit/Source/core/input/GestureManager.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/GestureManager.h"
 
 #include "core/dom/Document.h"
 #include "core/editing/SelectionController.h"
 #include "core/events/GestureEvent.h"
 #include "core/frame/FrameHost.h"
@@ skipping 236 matching lines @@
 }
 
 WebInputEventResult GestureManager::handleGestureLongPress(const GestureEventWithHitTestResults& targetedEvent)
 {
     const PlatformGestureEvent& gestureEvent = targetedEvent.event();
 
     // FIXME: Ideally we should try to remove the extra mouse-specific hit-tests here (re-using the
     // supplied HitTestResult), but that will require some overhaul of the touch drag-and-drop code
     // and LongPress is such a special scenario that it's unlikely to matter much in practice.
 
+    IntPoint hitTestPoint = m_frame->view()->rootFrameToContents(gestureEvent.position());

[dtapuska, 2016/08/17 13:39:49]

Seems reasonable. I'd like to see a test exercising this behavior though.

Moving the hit test before the handleDragDropIfPossible seemed dangerous at
first because what about DOM mutations. But after a further examination the
handleDragDropIfPossible returns true if it dispatches an event into JS so I
wouldn't expect any mutations to the DOM.

[hush (inactive), 2016/08/17 18:09:46]

Is it OK for the test to be Android only? The added logic is Android only.

[dtapuska, 2016/08/17 18:12:46]

I believe there are virtual LayoutTests for android under
third_party/WebKit/LayoutTests/virtual/android/*. But best to check with someone
who has written a test in that directory.

+    HitTestResult hitTestResult = m_frame->eventHandler().hitTestResultAtPoint(hitTestPoint);
+
     m_longTapShouldInvokeContextMenu = false;
-    if (m_frame->eventHandler().handleDragDropIfPossible(targetedEvent)) {
+    bool willTryDragDrop = true;
+
+#if OS(ANDROID)
+    if (hitTestResult.URLElement() || !hitTestResult.absoluteLinkURL().isNull() || !hitTestResult.absoluteImageURL().isNull() || !hitTestResult.absoluteMediaURL().isNull())
+        willTryDragDrop = false;
+#endif
+    if (willTryDragDrop && m_frame->eventHandler().handleDragDropIfPossible(targetedEvent)) {
         m_longTapShouldInvokeContextMenu = true;
         return WebInputEventResult::HandledSystem;
     }
-    IntPoint hitTestPoint = m_frame->view()->rootFrameToContents(gestureEvent.position());
-    HitTestResult result = m_frame->eventHandler().hitTestResultAtPoint(hitTestPoint);
-    if (m_selectionController->handleGestureLongPress(gestureEvent, result)) {
+
+    if (m_selectionController->handleGestureLongPress(gestureEvent, hitTestResult)) {
         m_frame->eventHandler().focusDocumentView();
         return WebInputEventResult::HandledSystem;
     }
 
     return sendContextMenuEventForGesture(targetedEvent);
 }
 
 WebInputEventResult GestureManager::handleGestureLongTap(const GestureEventWithHitTestResults& targetedEvent)
 {
 #if !OS(ANDROID)
@@ skipping 71 matching lines @@
 
     return &m_frame->page()->frameHost();
 }
 
 double GestureManager::getLastShowPressTimestamp() const
 {
     return m_lastShowPressTimestamp;
 }
 
 } // namespace blink