Enable touch-initiated drag-drop work on Windows

content/browser/web_contents/web_drag_source_win.h

Index: content/browser/web_contents/web_drag_source_win.h
diff --git a/content/browser/web_contents/web_drag_source_win.h b/content/browser/web_contents/web_drag_source_win.h
index 72d4a1692a243afb8ab7a3394de5e329d154a20c..c8afb00a108ceafce43abf49699427526ee328f1 100644
--- a/content/browser/web_contents/web_drag_source_win.h
+++ b/content/browser/web_contents/web_drag_source_win.h
@@ -29,7 +29,9 @@ class WebDragSource : public ui::DragSourceWin,
                       public NotificationObserver {
  public:
   // Create a new DragSource for a given HWND and WebContents.
-  WebDragSource(gfx::NativeWindow source_wnd, WebContents* web_contents);
+  WebDragSource(gfx::NativeWindow source_wnd,
+                WebContents* web_contents,
+                ui::DragDropTypes::DragEventSource event_source);
   virtual ~WebDragSource();
 
   // NotificationObserver implementation.
@@ -57,6 +59,8 @@ class WebDragSource : public ui::DragSourceWin,
   // by posting a task to this function.
   void DelayedOnDragSourceDrop();
 
+  void CancelLongPressGestureIfNeeded();
+
   // Keep a reference to the window so we can translate the cursor position.
   gfx::NativeWindow source_wnd_;