Move ScrollSnapPoints to its own file.

third_party/WebKit/Source/core/style/ScrollSnapPoints.h

+// Copyright 2017 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 ScrollSnapPoints_h
+#define ScrollSnapPoints_h
+
+#include <memory>
+#include "platform/Length.h"
+
+namespace blink {
+
+struct ScrollSnapPoints {
+  DISALLOW_NEW();
+
+  ScrollSnapPoints()
+      : repeat_offset(100, kPercent), has_repeat(false), uses_elements(false) {}
+
+  bool operator==(const ScrollSnapPoints& other) const {
+    return repeat_offset == other.repeat_offset &&
+           has_repeat == other.has_repeat &&
+           uses_elements == other.uses_elements;
+  }
+  bool operator!=(const ScrollSnapPoints& other) const {
+    return !(*this == other);
+  }
+
+  Length repeat_offset;
+  bool has_repeat;
+  bool uses_elements;
+};
+
+}  // namespace blink
+
+#endif  // ScrollSnapPoints_h