Move OSExchangeData from src/app to src/ui/base/dragdrop...

views/widget/widget_gtk.h

Index: views/widget/widget_gtk.h
===================================================================
--- views/widget/widget_gtk.h	(revision 71050)
+++ views/widget/widget_gtk.h	(working copy)
@@ -15,13 +15,17 @@
 #include "views/focus/focus_manager.h"
 #include "views/widget/widget.h"
 
-class OSExchangeData;
-class OSExchangeDataProviderGtk;
-
 namespace gfx {
 class Rect;
 }
 
+namespace ui {
+class OSExchangeData;
+class OSExchangeDataProviderGtk;
+}
+using ui::OSExchangeData;
+using ui::OSExchangeDataProviderGtk;
+
 namespace views {
 
 class DefaultThemeProvider;