aura: Add flag to indicate if a drag session is started with touch or mouse.

ui/views/drag_utils.h

Index: ui/views/drag_utils.h
diff --git a/ui/views/drag_utils.h b/ui/views/drag_utils.h
index 068cda1144168d30aaccf38aeb1913b78dc8c91c..158f5cdecab0070130b6631a52995416dea87b8a 100644
--- a/ui/views/drag_utils.h
+++ b/ui/views/drag_utils.h
@@ -5,6 +5,7 @@
 #ifndef UI_VIEWS_DRAG_UTILS_H_
 #define UI_VIEWS_DRAG_UTILS_H_
 
+#include "ui/base/dragdrop/drag_drop_types.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/views/views_export.h"
 
@@ -23,9 +24,10 @@ class Widget;
 
 // Starts a drag operation. This blocks until the drag operation completes.
 VIEWS_EXPORT void RunShellDrag(gfx::NativeView view,
-                            const ui::OSExchangeData& data,
-                            const gfx::Point& location,
-                            int operation);
+                               const ui::OSExchangeData& data,
+                               const gfx::Point& location,
+                               int operation,
+                               ui::DragDropTypes::DragEventSource source);
 
 // Returns a canvas that can be used to draw the drag image. Caller owns the
 // returned object. |widget| is Widget hosting the view being dragged.