Implement the framework for a paint property hierarchy

third_party/WebKit/Source/platform/graphics/paint/PaintProperties.h

-// Copyright 2015 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef PaintProperties_h
-#define PaintProperties_h
-
-#include <iosfwd>
-
-namespace blink {
-
-// The set of paint properties applying to a |PaintChunk|.
-// In particular, this does not mean properties like background-color, but
-// rather the hierarchy of transforms, clips, effects, etc. that apply to a
-// contiguous chunk of drawings.
-struct PaintProperties {
-    // TODO(jbroman): Add actual properties.
-};
-
-inline bool operator==(const PaintProperties&, const PaintProperties&)
-{
-    return true;
-}
-
-inline bool operator!=(const PaintProperties& a, const PaintProperties& b)
-{
-    return !(a == b);
-}
-
-// Redeclared here to avoid ODR issues.
-// See platform/testing/PaintPrinters.h.
-void PrintTo(const PaintProperties&, std::ostream*);
-
-} // namespace blink
-
-#endif // PaintProperties_h