Add SkSourceGammaTreatment enum so we know how to create mips

include/gpu/SkGr.h

Index: include/gpu/SkGr.h
diff --git a/include/gpu/SkGr.h b/include/gpu/SkGr.h
index 6a73636c69047e26e70dbcd39127f378bd88c658..edfcd6d813b9049bf69a7d16df015a7616c05e7d 100644
--- a/include/gpu/SkGr.h
+++ b/include/gpu/SkGr.h
@@ -68,7 +68,8 @@ static inline GrColor SkPMColorToGrColor(SkPMColor c) {
 /** Returns a texture representing the bitmap that is compatible with the GrTextureParams. The
     texture is inserted into the cache (unless the bitmap is marked volatile) and can be
     retrieved again via this function. */
-GrTexture* GrRefCachedBitmapTexture(GrContext*, const SkBitmap&, const GrTextureParams&);
+GrTexture* GrRefCachedBitmapTexture(GrContext*, const SkBitmap&, const GrTextureParams&,
+                                    SkSourceGammaTreatment);
 
 // TODO: Move SkImageInfo2GrPixelConfig to SkGrPriv.h (requires cleanup to SkWindow its subclasses).
 GrPixelConfig SkImageInfo2GrPixelConfig(SkColorType, SkAlphaType, SkColorProfileType, const GrCaps&);