add peekPixels to canvas

include/core/SkBitmapDevice.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 SkBitmapDevice_DEFINED
 #define SkBitmapDevice_DEFINED
@@ skipping 260 matching lines @@
     virtual SkBaseDevice* onCreateCompatibleDevice(SkBitmap::Config config,
                                                    int width, int height,
                                                    bool isOpaque,
                                                    Usage usage) SK_OVERRIDE;
 
     /** Causes any deferred drawing to the device to be completed.
      */
     virtual void flush() SK_OVERRIDE {}
 
     virtual SkSurface* newSurface(const SkImageInfo&) SK_OVERRIDE;
+    virtual const void* peekPixels(SkImageInfo*, size_t* rowBytes) SK_OVERRIDE;
 
     SkBitmap    fBitmap;
 
     typedef SkBaseDevice INHERITED;
 };
 
 #endif // SkBitmapDevice_DEFINED