Bug 1352339 - Add missing WinCompositorWidget.h include to nsWindowsGfx.cpp r=jwatt

We need the definition of CompositorWidgetDelegate in order to use
mCompositorWidgetDelegate.

MozReview-Commit-ID: Gr5G0SvCckk

--HG--
extra : rebase_source : 17db54c13bebb97c2d39e2dc0b69b7ad28346385

widget/windows/nsWindowGfx.cpp

@@ -48,6 +48,7 @@ using mozilla::plugins::PluginInstanceParent;
 #include "mozilla/layers/CompositorBridgeParent.h"
 #include "mozilla/layers/CompositorBridgeChild.h"
 #include "ClientLayerManager.h"
+#include "WinCompositorWidget.h"
 
 #include "nsUXThemeData.h"
 #include "nsUXThemeConstants.h"