Make SkImage_Gpu share it's pixelref with the surface to prevent premature return to scratch pool.

include/core/SkImage.h

Index: include/core/SkImage.h
===================================================================
--- include/core/SkImage.h	(revision 10357)
+++ include/core/SkImage.h	(working copy)
@@ -65,8 +65,14 @@
     static SkImage* NewRasterCopy(const Info&, const void* pixels, size_t rowBytes);
     static SkImage* NewRasterData(const Info&, SkData* pixels, size_t rowBytes);
     static SkImage* NewEncodedData(SkData*);
-    static SkImage* NewTexture(GrTexture*);
 
+    /**
+     * GrTexture is a more logical parameter for this factory, but its 
+     * interactions with scratch cache still has issues, so for now we take
+     * SkBitmap instead. This will be changed in the future. skbug.com/1449
+     */
+    static SkImage* NewTexture(const SkBitmap&);
+
     int width() const { return fWidth; }
     int height() const { return fHeight; }
     uint32_t uniqueID() const { return fUniqueID; }