Shim to enforce that canvas virtuals are overridden

Change-Id: Iad70d449bbc43195baefd70d20c41996a8435e6e
Reviewed-on: https://skia-review.googlesource.com/113320
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Brian Osman <brianosman@google.com>
diff --git a/src/core/SkRecorder.cpp b/src/core/SkRecorder.cpp
index 9374b60..3c4aff3 100644
--- a/src/core/SkRecorder.cpp
+++ b/src/core/SkRecorder.cpp
@@ -36,14 +36,14 @@
 ///////////////////////////////////////////////////////////////////////////////////////////////
 
 SkRecorder::SkRecorder(SkRecord* record, int width, int height, SkMiniRecorder* mr)
-    : SkNoDrawCanvas(width, height)
+    : SkCanvasVirtualEnforcer<SkNoDrawCanvas>(width, height)
     , fDrawPictureMode(Record_DrawPictureMode)
     , fApproxBytesUsedBySubPictures(0)
     , fRecord(record)
     , fMiniRecorder(mr) {}
 
 SkRecorder::SkRecorder(SkRecord* record, const SkRect& bounds, SkMiniRecorder* mr)
-    : SkNoDrawCanvas(bounds.roundOut())
+    : SkCanvasVirtualEnforcer<SkNoDrawCanvas>(bounds.roundOut())
     , fDrawPictureMode(Record_DrawPictureMode)
     , fApproxBytesUsedBySubPictures(0)
     , fRecord(record)