cc: Replace Region with SimpleEnclosedRegion for occlusion tracking

cc/base/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 "cc/base/region.h"
+
 #include "base/debug/trace_event_argument.h"
 #include "base/values.h"
+#include "cc/base/simple_enclosed_region.h"
 
 namespace cc {
 
 Region::Region() {
 }
 
 Region::Region(const Region& region)
     : skregion_(region.skregion_) {
 }
 
@@ skipping 55 matching lines @@
 }
 
 void Region::Subtract(const gfx::Rect& rect) {
   skregion_.op(gfx::RectToSkIRect(rect), SkRegion::kDifference_Op);
 }
 
 void Region::Subtract(const Region& region) {
   skregion_.op(region.skregion_, SkRegion::kDifference_Op);
 }
 
+void Region::Subtract(const SimpleEnclosedRegion& region) {
+  for (size_t i = 0; i < region.GetRegionComplexity(); ++i) {
+    skregion_.op(gfx::RectToSkIRect(region.GetRect(i)),
+                 SkRegion::kDifference_Op);
+  }
+}
+
 void Region::Union(const gfx::Rect& rect) {
   skregion_.op(gfx::RectToSkIRect(rect), SkRegion::kUnion_Op);
 }
 
 void Region::Union(const Region& region) {
   skregion_.op(region.skregion_, SkRegion::kUnion_Op);
 }
 
 void Region::Intersect(const gfx::Rect& rect) {
   skregion_.op(gfx::RectToSkIRect(rect), SkRegion::kIntersect_Op);
@@ skipping 42 matching lines @@
 }
 
 Region::Iterator::Iterator(const Region& region)
     : it_(region.skregion_) {
 }
 
 Region::Iterator::~Iterator() {
 }
 
 }  // namespace cc