Make SkCanvas::getBaseLayerSize() virtual

include/core/SkCanvas.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkCanvas_DEFINED
 #define SkCanvas_DEFINED
 
@@ skipping 112 matching lines @@
     /**
      *  Trigger the immediate execution of all pending draw operations.
      */
     void flush();
 
     /**
      * Gets the size of the base or root layer in global canvas coordinates. The
      * origin of the base layer is always (0,0). The current drawable area may be
      * smaller (due to clipping or saveLayer).
      */
-    SkISize getBaseLayerSize() const;
+    virtual SkISize getBaseLayerSize() const;
 
     /**
      *  DEPRECATED: call getBaseLayerSize
      */
     SkISize getDeviceSize() const { return this->getBaseLayerSize(); }
 
     /**
      *  DEPRECATED.
      *  Return the canvas' device object, which may be null. The device holds
      *  the bitmap of the pixels that the canvas draws into. The reference count
@@ skipping 1346 matching lines @@
 
 class SkCanvasClipVisitor {
 public:
     virtual ~SkCanvasClipVisitor();
     virtual void clipRect(const SkRect&, SkRegion::Op, bool antialias) = 0;
     virtual void clipRRect(const SkRRect&, SkRegion::Op, bool antialias) = 0;
     virtual void clipPath(const SkPath&, SkRegion::Op, bool antialias) = 0;
 };
 
 #endif