start to remove lockPixels from bitmapshader

include/core/SkPixelRef.h

Index: include/core/SkPixelRef.h
diff --git a/include/core/SkPixelRef.h b/include/core/SkPixelRef.h
index 0487e426109a2e84381e84aff4638ec0c6eccfb3..395fb93607b90a25d2f01bf21ee9b9ceb105b6d2 100644
--- a/include/core/SkPixelRef.h
+++ b/include/core/SkPixelRef.h
@@ -141,6 +141,21 @@ public:
         return this->onRefEncodedData();
     }
 
+    /**
+     *  Return a decoded instance of this pixelRef in bitmap. If this cannot be
+     *  done, return false and ignore bitmap.
+     *  pow2 is the requeste power-of-two downscale that the caller needs. This
+     *  can be ignored, and the "original" size can be returned, but if the
+     *  underlying codec can efficiently return a smaller size, that should be
+     *  done.
+     *  If this returns true, then bitmap must be "locked" and point to the
+     *  pixels for this pixelref.
+     */
+    bool decodeInto(int pow2, SkBitmap* bitmap) {
+        SkASSERT(pow2 >= 0);
+        return this->onDecodeInto(pow2, bitmap);
+    }
+
     /** Are we really wrapping a texture instead of a bitmap?
      */
     virtual GrTexture* getTexture() { return NULL; }
@@ -190,6 +205,8 @@ protected:
     /** Default impl returns true */
     virtual bool onLockPixelsAreWritable() const;
 
+    virtual bool onDecodeInto(int pow2, SkBitmap* bitmap);
+
     /**
      *  For pixelrefs that don't have access to their raw pixels, they may be
      *  able to make a copy of them (e.g. if the pixels are on the GPU).