cc: Define Region::Contains() to be A contains B if all points in B are also in A.

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 29 matching lines @@
 
 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 {
+  if (rect.IsEmpty())
+    return true;
   return skregion_.contains(ToSkIRect(rect));
 }
 
 bool Region::Contains(const Region& region) const {
+  if (region.IsEmpty())
+    return true;
   return skregion_.contains(region.skregion_);
 }
 
 bool Region::Intersects(gfx::Rect rect) const {
   return skregion_.intersects(ToSkIRect(rect));
 }
 
 bool Region::Intersects(const Region& region) const {
   return skregion_.intersects(region.skregion_);
 }
@@ skipping 36 matching lines @@
 }
 
 Region::Iterator::Iterator(const Region& region)
     : it_(region.skregion_) {
 }
 
 Region::Iterator::~Iterator() {
 }
 
 }  // namespace cc