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/src/images/SkImageRef.cpp b/src/images/SkImageRef.cpp
index 16c2820..7d2d416 100644
--- a/src/images/SkImageRef.cpp
+++ b/src/images/SkImageRef.cpp
@@ -57,6 +57,16 @@
     return true;
 }
 
+bool SkImageRef::isOpaque(SkBitmap* bitmap) {
+    if (bitmap && bitmap->pixelRef() == this) {
+        bitmap->lockPixels();
+        bitmap->setIsOpaque(fBitmap.isOpaque());
+        bitmap->unlockPixels();
+        return true;
+    }
+    return false;
+}
+
 SkImageDecoderFactory* SkImageRef::setDecoderFactory(
                                                 SkImageDecoderFactory* fact) {
     SkRefCnt_SafeAssign(fFactory, fact);