respect srgb gamma when building mips

include/core/SkImageInfo.h

Index: include/core/SkImageInfo.h
diff --git a/include/core/SkImageInfo.h b/include/core/SkImageInfo.h
index 743ca5948137f0cd7e8d816bc4b2a3c45c84981a..7dae2546453d689d84b6696037155a6c2843c6f8 100644
--- a/include/core/SkImageInfo.h
+++ b/include/core/SkImageInfo.h
@@ -280,6 +280,10 @@ public:
         return SkImageInfo(fWidth, fHeight, newColorType, fAlphaType, fProfileType, fColorSpace);
     }
 
+    SkImageInfo makeColorSpace(sk_sp<SkColorSpace> cs) const {
+        return SkImageInfo::Make(fWidth, fHeight, fColorType, fAlphaType, std::move(cs));
+    }
+
     int bytesPerPixel() const { return SkColorTypeBytesPerPixel(fColorType); }
 
     int shiftPerPixel() const { return SkColorTypeShiftPerPixel(fColorType); }