Suppress drag and drop on links on touch screen.

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

Index: third_party/WebKit/Source/core/input/GestureManager.cpp
diff --git a/third_party/WebKit/Source/core/input/GestureManager.cpp b/third_party/WebKit/Source/core/input/GestureManager.cpp
index bb56ddba8fd8f4a17637580c017a1e3880187b65..b48db20b9a43817a5db53c8d1fc21992d64b110e 100644
--- a/third_party/WebKit/Source/core/input/GestureManager.cpp
+++ b/third_party/WebKit/Source/core/input/GestureManager.cpp
@@ -254,14 +254,22 @@ WebInputEventResult GestureManager::handleGestureLongPress(const GestureEventWit
     // 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;
     }