Add SkImage factory method that forces image to be resolved to a texture.

include/core/SkImage.h

Index: include/core/SkImage.h
diff --git a/include/core/SkImage.h b/include/core/SkImage.h
index 62a9e9cf426bc132ded0e4fad45aa76306361b0f..43bfeadf688e99996cf5b5c63b7851395406707c 100644
--- a/include/core/SkImage.h
+++ b/include/core/SkImage.h
@@ -142,6 +142,13 @@ public:
                                            const SkISize yuvSizes[3],
                                            GrSurfaceOrigin);
 
+    /**
+     *  Ensures that an image is backed by a texture (when GrContext is non-null). If no
+     *  transformation is required, the returned image may be the same as the one passed in.
+     *  If the input image is from a different GrContext, this will fail.
+     */
+    static SkImage* NewTextureImageFromImage(GrContext*, SkImage*);

[reed1, 2016/01/29 17:19:10]

nit:

SkImage* newTextureImage(GrContext*) const;

ala newSubset()

+
     static SkImage* NewFromPicture(const SkPicture*, const SkISize& dimensions,
                                    const SkMatrix*, const SkPaint*);