Fixed bug with SkImage leaving canvas backing store in an immutable state after destroy.

src/image/SkImage_Raster.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkImage_Base.h"
 #include "SkImagePriv.h"
 #include "SkBitmap.h"
@@ skipping 82 matching lines @@
 }
 
 SkImage_Raster::SkImage_Raster(const Info& info, SkPixelRef* pr, size_t rowBytes)
 : INHERITED(info.fWidth, info.fHeight) {
     bool isOpaque;
     SkBitmap::Config config = SkImageInfoToBitmapConfig(info, &isOpaque);
 
     fBitmap.setConfig(config, info.fWidth, info.fHeight, rowBytes);
     fBitmap.setPixelRef(pr);
     fBitmap.setIsOpaque(isOpaque);
-    fBitmap.setImmutable();
 }
 
 SkImage_Raster::~SkImage_Raster() {}
 
 void SkImage_Raster::onDraw(SkCanvas* canvas, SkScalar x, SkScalar y, const SkPaint* paint) {
     canvas->drawBitmap(fBitmap, x, y, paint);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
@@ skipping 38 matching lines @@
 }
 
 SkImage* SkNewImageFromPixelRef(const SkImage::Info& info, SkPixelRef* pr,
                                 size_t rowBytes) {
     return SkNEW_ARGS(SkImage_Raster, (info, pr, rowBytes));
 }
 
 SkPixelRef* SkBitmapImageGetPixelRef(SkImage* image) {
     return ((SkImage_Raster*)image)->getPixelRef();
 }