merge from android tree:
- optional parameters added to descriptorProc and allocPixels
- clip options to image decoders
- check for xfermode in blitter_a8
- UNROLL loops in blitrow

reviewed by reed@google.com



git-svn-id: http://skia.googlecode.com/svn/trunk@841 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/images/SkImageRef.h b/include/images/SkImageRef.h
index 9c9896f..800f12e 100644
--- a/include/images/SkImageRef.h
+++ b/include/images/SkImageRef.h
@@ -57,6 +57,12 @@
     */
     bool getInfo(SkBitmap* bm);
     
+    /** Return true if the image can be decoded and is opaque. Calling this
+        method will decode and set the pixels in the specified bitmap and
+        sets the isOpaque flag.
+     */
+    bool isOpaque(SkBitmap* bm);
+    
     SkImageDecoderFactory* getDecoderFactory() const { return fFactory; }
     // returns the factory parameter
     SkImageDecoderFactory* setDecoderFactory(SkImageDecoderFactory*);