Backed out changeset af0d7fedc60f (bug 1162050)

dom/events/EventStateManager.cpp

@@ -1784,7 +1784,9 @@ EventStateManager::GenerateDragGesture(nsPresContext* aPresContext,
       // Set the current target to the content for the mouse down
       mCurrentTargetContent = targetContent;
 
-      // Dispatch the dragstart event to the DOM.
+      // Dispatch both the dragstart and draggesture events to the DOM. For
+      // elements in an editor, only fire the draggesture event so that the
+      // editor code can handle it but content doesn't see a dragstart.
       nsEventStatus status = nsEventStatus_eIgnore;
       EventDispatcher::Dispatch(targetContent, aPresContext, &startEvent,
                                 nullptr, &status);
@@ -1801,7 +1803,7 @@ EventStateManager::GenerateDragGesture(nsPresContext* aPresContext,
       }
 
       // now that the dataTransfer has been updated in the dragstart and
-      // draggesture events, make it read only so that the data doesn't
+      // draggesture events, make it readonly so that the data doesn't
       // change during the drag.
       dataTransfer->SetReadOnly();
 
@@ -1814,6 +1816,10 @@ EventStateManager::GenerateDragGesture(nsPresContext* aPresContext,
         }
       }
 
+      // Note that frame event handling doesn't care about eLegacyDragGesture,
+      // which is just as well since we don't really know which frame to
+      // send it to
+
       // Reset mCurretTargetContent to what it was
       mCurrentTargetContent = targetBeforeEvent;
     }
@@ -1918,7 +1924,7 @@ EventStateManager::DoDefaultDragStart(nsPresContext* aPresContext,
   if (!dragService)
     return false;
 
-  // Default handling for the dragstart event.
+  // Default handling for the draggesture/dragstart event.
   //
   // First, check if a drag session already exists. This means that the drag
   // service was called directly within a draggesture handler. In this case,

dom/events/EventStateManager.h

@@ -855,11 +855,11 @@ protected:
                                          nsIContent** aTargetNode);
 
   /*
-   * Perform the default handling for the dragstart event and set up a
+   * Perform the default handling for the dragstart/draggesture event and set up a
    * drag for aDataTransfer if it contains any data. Returns true if a drag has
    * started.
    *
-   * aDragEvent - the dragstart event
+   * aDragEvent - the dragstart/draggesture event
    * aDataTransfer - the data transfer that holds the data to be dragged
    * aDragTarget - the target of the drag
    * aSelection - the selection to be dragged