Update SkSurface MakeFromBackend* factories to take an SkColorType.

Bug: skia:
Change-Id: Ib1b03b1181ec937843eac2e8d8cb03ebe53e32c1
Reviewed-on: https://skia-review.googlesource.com/86760
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
diff --git a/src/gpu/mtl/GrMtlCaps.h b/src/gpu/mtl/GrMtlCaps.h
index bc8aac9..70ff74f 100644
--- a/src/gpu/mtl/GrMtlCaps.h
+++ b/src/gpu/mtl/GrMtlCaps.h
@@ -56,11 +56,16 @@
         return false;
     }
 
-private:
-    bool onValidateBackendTexture(GrBackendTexture* tex, SkColorType ct) const override {
+    bool validateBackendTexture(const GrBackendTexture&, SkColorType,
+                                GrPixelConfig*) const override {
+        return false;
+    }
+    bool validateBackendRenderTarget(const GrBackendRenderTarget&, SkColorType,
+                                     GrPixelConfig*) const override {
         return false;
     }
 
+private:
     void initFeatureSet(MTLFeatureSet featureSet);
 
     void initGrCaps(const id<MTLDevice> device);