Update NulCanvas so everything builds.

experimental/PdfViewer/SkNulCanvas.h

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkNulCanvas_DEFINED
 #define SkNulCanvas_DEFINED
 
@@ skipping 64 matching lines @@
                       const SkPaint& paint) override {}
     void onDrawRect(const SkRect& rect, const SkPaint& paint) override {}
     void onDrawOval(const SkRect& oval, const SkPaint&) override {}
     void onDrawRRect(const SkRRect& rrect, const SkPaint& paint) override {}
     void onDrawPath(const SkPath& path, const SkPaint& paint) override {}
     void onDrawBitmap(const SkBitmap& bitmap, SkScalar left, SkScalar top,
                       const SkPaint* paint = NULL) override {}
     void onDrawBitmapRect(const SkBitmap& bitmap, const SkRect* src,
                           const SkRect& dst,
                           const SkPaint* paint,
-                          SK_VIRTUAL_CONSTRAINT_TYPE) override {}
+                          SkCanvas::SrcRectConstraint) override {}
     void onDrawImage(const SkImage*, SkScalar left, SkScalar top, const SkPaint*) override {}
-    void onDrawImageRect(const SkImage*, const SkRect*, const SkRect&, const SkPaint*
-                         SRC_RECT_CONSTRAINT_PARAM(constraint)) override {}
+    void onDrawImageRect(const SkImage*, const SkRect*, const SkRect&, const SkPaint*,
+                         SkCanvas::SrcRectConstraint) override {}
     void onDrawBitmapNine(const SkBitmap& bitmap, const SkIRect& center,
                           const SkRect& dst, const SkPaint* paint = NULL) override {}
     void onDrawSprite(const SkBitmap& bitmap, int left, int top,
                       const SkPaint* paint = NULL) override {}
     void onDrawVertices(VertexMode vmode, int vertexCount,
                         const SkPoint vertices[], const SkPoint texs[],
                         const SkColor colors[], SkXfermode* xmode,
                         const uint16_t indices[], int indexCount,
                         const SkPaint& paint) override {}
 
 
 private:
     typedef SkCanvas INHERITED;
 };
 
 #endif  // SkNulCanvas_DEFINED