add peekPixels to canvas

src/image/SkImagePriv.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkImagePriv_DEFINED
 #define SkImagePriv_DEFINED
 
 #include "SkBitmap.h"
 #include "SkImage.h"
 
 class SkPicture;
 
 extern SkBitmap::Config SkImageInfoToBitmapConfig(const SkImageInfo&);
-extern SkBitmap::Config SkColorTypeToBitmapConfig(SkColorType);
-extern SkColorType SkBitmapConfigToColorType(SkBitmap::Config);
 
 // Call this if you explicitly want to use/share this pixelRef in the image
 extern SkImage* SkNewImageFromPixelRef(const SkImageInfo&, SkPixelRef*,
                                        size_t rowBytes);
 
 /**
  *  Examines the bitmap to decide if it can share the existing pixelRef, or
  *  if it needs to make a deep-copy of the pixels. The bitmap's pixelref will
  *  be shared if either the bitmap is marked as immutable, or canSharePixelRef
  *  is true.
@@ skipping 32 matching lines @@
 // may be called to see if the surface and the image share the same GrTexture,
 // in which case the surface may need to perform a copy-on-write.
 extern GrTexture* SkTextureImageGetTexture(SkImage* textureImage);
 
 // Update the texture wrapped by an image created with NewTexture. This
 // is called when a surface and image share the same GrTexture and the
 // surface needs to perform a copy-on-write
 extern void SkTextureImageSetTexture(SkImage* image, GrTexture* texture);
 
 #endif