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());
+    HitTestResult hitTestResult = m_frame->eventHandler().hitTestResultAtPoint(hitTestPoint);
+
     m_longTapShouldInvokeContextMenu = false;
-    if (m_frame->eventHandler().handleDragDropIfPossible(targetedEvent)) {
+    bool hitTestContainsLinks = hitTestResult.URLElement() || !hitTestResult.absoluteLinkURL().isNull() || !hitTestResult.absoluteImageURL().isNull() || !hitTestResult.absoluteMediaURL().isNull();

[dcheng, 2016/08/29 19:45:08]

This isn't just links, right? It's images and videos as well?

Alo, why do we needto check URLElement() and absoluteLinkURL().isNull()?

[hush (inactive), 2016/08/29 20:49:49]

Yes. Long pressing on images and videos should open context menu as well,
instead of staring DnD. Otherwise, the user can't open context menu on these
things any more.

We need to check URLElement() and absoluteLinkURL().isNull() because they are
only for links, both URLElement() and absoluteLinkURL() can be null when the
user is long pressing on an image.

[dcheng, 2016/08/29 21:10:03]

As discussed offline, I think we can just check HitTestResult::URLElement().

[hush (inactive), 2016/08/29 21:14:53]

Done.

+
+    if (!hitTestContainsLinks && 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