Make filters use SkImage instead of SkBitmap

include/core/SkImage.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 SkImage_DEFINED
 #define SkImage_DEFINED
 
@@ skipping 169 matching lines @@
     /**
      *  Draw the image, cropped to the src rect, to the dst rect of a canvas.
      *  If src is larger than the bounds of the image, the rest of the image is
      *  filled with transparent black pixels.
      *
      *  See SkCanvas::drawBitmapRectToRect for similar behavior.
      */
     void drawRect(SkCanvas*, const SkRect* src, const SkRect& dst, const SkPaint*) const;
 };
 
+/** A helper for common in pixel access done with CPU: lock pixels of the rendering of the
+ * image in N32 format, or fail. The condition bitmap->getPixels() != NULL signifies success.
+ * Will unref the image if succesful, as this may save memory.
+ */
+class SkAutoAdoptImageAsN32Bitmap : SkNoncopyable {
+public:
+    /**
+     * @param image image to adopt as bitmap. will be reset(NULL) if operation is successful.
+     */
+    SkAutoAdoptImageAsN32Bitmap(SkAutoTUnref<const SkImage>& image, SkBitmap* bitmap);
+    ~SkAutoAdoptImageAsN32Bitmap() {
+        if (fBitmap) {
+            fBitmap->unlockPixels();
+        }
+    }
+private:
+    SkBitmap* fBitmap;
+};
+
+/** A helper for common in pixel access done with CPU: lock pixels of the rendering of the
+ * image in N32 format, or fail. The condition bitmap->getPixels() != NULL signifies success.
+ */
+class SkAutoImageAsN32Bitmap : SkNoncopyable {
+public:
+    SkAutoImageAsN32Bitmap(const SkImage* image, SkBitmap* bitmap);
+    ~SkAutoImageAsN32Bitmap() {
+        if (fBitmap) {
+            fBitmap->unlockPixels();
+        }
+    }
+private:
+    SkBitmap* fBitmap;
+};
+
 #endif