bug 794038 followup - add #include "nsIPresShell.h" to nsChildView.mm to avoid relying on fragile indirect inclusion. rs=Ms2ger

widget/cocoa/nsChildView.mm

@@ -32,6 +32,7 @@
 #include "nsNPAPIPluginInstance.h"
 #include "nsThemeConstants.h"
 #include "nsIWidgetListener.h"
+#include "nsIPresShell.h"
 
 #include "nsDragService.h"
 #include "nsClipboard.h"