Support MSAA in the picture debugger

debugger/QT/SkCanvasWidget.h

Index: debugger/QT/SkCanvasWidget.h
diff --git a/debugger/QT/SkCanvasWidget.h b/debugger/QT/SkCanvasWidget.h
index 0dcb470405e3b60082ed1c7bc75b56228c0d6f0f..330861342fcddb8d6a635c205cde939285034c30 100644
--- a/debugger/QT/SkCanvasWidget.h
+++ b/debugger/QT/SkCanvasWidget.h
@@ -36,6 +36,10 @@ public:
 
     void setWidgetVisibility(WidgetType type, bool isHidden);
 
+#if SK_SUPPORT_GPU
+    void setGLSampleCount(int sampleCount);
+#endif
+
     /** Zooms the canvas by scale with the transformation centered at the widget point (px, py). */
     void zoom(float scale, int px, int py);