cc: Expose clear and swap on Region

cc/region.cc

 // Copyright (c) 2012 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 "config.h"
 
 #include "cc/region.h"
 
 namespace cc {
 
@@ skipping 20 matching lines @@
 const Region& Region::operator=(gfx::Rect rect) {
   skregion_ = SkRegion(ToSkIRect(rect));
   return *this;
 }
 
 const Region& Region::operator=(const Region& region) {
   skregion_ = region.skregion_;
   return *this;
 }
 
+void Region::Swap(Region& region) {
+  region.skregion_.swap(skregion_);
+}
+
+void Region::Clear() {
+  skregion_.setEmpty();
+}
+
 bool Region::IsEmpty() const {
   return skregion_.isEmpty();
 }
 
 bool Region::Contains(gfx::Point point) const {
   return skregion_.contains(point.x(), point.y());
 }
 
 bool Region::Contains(gfx::Rect rect) const {
   return skregion_.contains(ToSkIRect(rect));
@@ skipping 49 matching lines @@
 }
 
 Region::Iterator::Iterator(const Region& region)
     : it_(region.skregion_) {
 }
 
 Region::Iterator::~Iterator() {
 }
 
 }  // namespace cc