Bug 923188: Add missing #include to HTMLCanvasElement.cpp, to fix build bustage with --disable-webgl. r=ehsan

content/html/content/src/HTMLCanvasElement.cpp

@@ -9,6 +9,7 @@
 #include "imgIEncoder.h"
 #include "jsapi.h"
 #include "jsfriendapi.h"
+#include "gfxImageSurface.h"
 #include "mozilla/Base64.h"
 #include "mozilla/CheckedInt.h"
 #include "mozilla/dom/CanvasRenderingContext2D.h"