Align drag feedback for links with draggable="true" to Safari.

third_party/WebKit/Source/core/page/DragController.cpp

Index: third_party/WebKit/Source/core/page/DragController.cpp
diff --git a/third_party/WebKit/Source/core/page/DragController.cpp b/third_party/WebKit/Source/core/page/DragController.cpp
index 5de205080b24a0b001d7a42737d5eab67d2173f2..a4b724a3438320ee95747e49d6df2ad6ba8a4596 100644
--- a/third_party/WebKit/Source/core/page/DragController.cpp
+++ b/third_party/WebKit/Source/core/page/DragController.cpp
@@ -798,15 +798,15 @@ Node* DragController::draggableNode(const LocalFrame* src,
         return node;
       }
       // Other draggable elements are considered unselectable.
+      if (dragMode == DRAG_ELEMENT) {
+        candidateDragType = DragSourceActionDHTML;
+        break;
+      }
       if (isHTMLAnchorElement(*node) &&
           toHTMLAnchorElement(node)->isLiveLink()) {
         candidateDragType = DragSourceActionLink;
         break;
       }
-      if (dragMode == DRAG_ELEMENT) {
-        candidateDragType = DragSourceActionDHTML;
-        break;
-      }
     }
   }
 
@@ -910,16 +910,36 @@ bool DragController::populateDragDataTransfer(LocalFrame* src,
     Element* element = toElement(node);
     prepareDataTransferForImageDrag(src, dataTransfer, element, linkURL,
                                     imageURL, hitTestResult.altDisplayString());
-  } else if (state.m_dragType == DragSourceActionLink) {
-    if (linkURL.isEmpty())
-      return false;
-    // Simplify whitespace so the title put on the clipboard resembles what the
-    // user sees on the web page. This includes replacing newlines with spaces.
-    dataTransfer->writeURL(node, linkURL,
-                           hitTestResult.textContent().simplifyWhiteSpace());
+  } else {
+    if (isHTMLAnchorElement(*node) && toHTMLAnchorElement(node)->isLiveLink() &&

[dcheng, 2016/10/31 22:31:35]

I was thinking we could make this a top-level if () with no else--it's default
behavior we want as long as the dragged node is a link, right? Or do we not want
this behavior if the link being dragged only contains an image? (I don't quite
remember how this case resolves itself)

[pwnall, 2016/11/04 23:08:29]

Done.
I'll learn about this more as I work through the feedback bugs and the image
bugs :D

+        !linkURL.isEmpty()) {
+      // Simplify whitespace so the title put on the clipboard resembles what
+      // the user sees on the web page. This includes replacing newlines with
+      // spaces.
+      dataTransfer->writeURL(node, linkURL,
+                             hitTestResult.textContent().simplifyWhiteSpace());
+    }
+
+    if (state.m_dragType == DragSourceActionLink) {
+      if (linkURL.isEmpty())
+        return false;
+    } else if (state.m_dragType == DragSourceActionDHTML) {
+      if (LayoutObject* layoutObject = node->layoutObject()) {
+        IntRect boundingIncludingDescendants =
+            layoutObject->absoluteBoundingBoxRectIncludingDescendants();
+        IntSize delta = dragOrigin - boundingIncludingDescendants.location();
+        dataTransfer->setDragImageElement(node, IntPoint(delta));
+      } else {
+        // The layoutObject has disappeared, this can happen if the onStartDrag
+        // handler has hidden the element in some way. In this case we just kill
+        // the drag.
+        return false;
+      }
+
+      // FIXME: For DHTML/draggable element drags, write element markup to
+      // clipboard.
+    }
   }
-  // FIXME: For DHTML/draggable element drags, write element markup to
-  // clipboard.
   return true;
 }