Replace cc::ViewportSelectionBound with gfx::SelectionBound

cc/output/viewport_selection_bound.cc

-// Copyright 2014 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.
-
-#include "cc/output/viewport_selection_bound.h"
-
-namespace cc {
-
-ViewportSelectionBound::ViewportSelectionBound()
-    : type(SELECTION_BOUND_EMPTY), visible(false) {
-}
-
-ViewportSelectionBound::~ViewportSelectionBound() {
-}
-
-bool operator==(const ViewportSelectionBound& lhs,
-                const ViewportSelectionBound& rhs) {
-  return lhs.type == rhs.type && lhs.visible == rhs.visible &&
-         lhs.edge_top == rhs.edge_top && lhs.edge_bottom == rhs.edge_bottom;
-}
-
-bool operator!=(const ViewportSelectionBound& lhs,
-                const ViewportSelectionBound& rhs) {
-  return !(lhs == rhs);
-}
-
-}  // namespace cc