Remove operator== from SkPaint

include/core/SkPaint.h

Index: include/core/SkPaint.h
diff --git a/include/core/SkPaint.h b/include/core/SkPaint.h
index fa0c61e4ea5f1813aee8902bccaa3ce937e07c63..6390b9e81dc95cbb526465e8ff2be56859e3f945 100644
--- a/include/core/SkPaint.h
+++ b/include/core/SkPaint.h
@@ -67,11 +67,6 @@ public:
 
     SkPaint& operator=(const SkPaint&);
 
-    SK_API friend bool operator==(const SkPaint& a, const SkPaint& b);
-    friend bool operator!=(const SkPaint& a, const SkPaint& b) {
-        return !(a == b);
-    }
-
     void flatten(SkFlattenableWriteBuffer&) const;
     void unflatten(SkFlattenableReadBuffer&);
 
@@ -1092,6 +1087,7 @@ private:
     friend class SkPDFDevice;
     friend class SkTextToPathIter;
     friend class SkCanonicalizePaint;
+    friend class PaintEqualityHelper;  // Defined in PaintTest.cpp
 
 #ifdef SK_BUILD_FOR_ANDROID
     SkPaintOptionsAndroid fPaintOptionsAndroid;