cc: Replace Region with SimpleEnclosedRegion for occlusion tracking

cc/base/simple_enclosed_region_unittest.cc

+// Copyright (c) 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/base/simple_enclosed_region.h"
+
+#include <algorithm>
+#include <vector>
+
+#include "base/logging.h"
+#include "cc/base/region.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace cc {
+namespace {
+
+bool ExpectRegionEq(const gfx::Rect& rect, const SimpleEnclosedRegion& region) {
+  std::vector<gfx::Rect> actual_rects;
+  std::vector<gfx::Rect> expected_rects;
+
+  if (!rect.IsEmpty())
+    expected_rects.push_back(rect);
+
+  for (size_t i = 0; i < region.GetRegionComplexity(); ++i)
+    actual_rects.push_back(region.GetRect(i));
+
+  if (rect.IsEmpty() != region.IsEmpty()) {
+    LOG(ERROR) << "Expected: " << rect.IsEmpty()
+               << " Actual: " << region.IsEmpty();
+    return false;
+  }
+
+  if (expected_rects.size() != actual_rects.size()) {
+    LOG(ERROR) << "Expected: " << expected_rects.size()
+               << " Actual: " << actual_rects.size();
+    return false;
+  }
+
+  std::sort(actual_rects.begin(), actual_rects.end());
+  std::sort(expected_rects.begin(), expected_rects.end());
+
+  for (size_t i = 0; i < expected_rects.size(); ++i) {
+    if (expected_rects[i] != actual_rects[i]) {
+      LOG(ERROR) << "Expected: " << expected_rects[i].ToString()
+                 << " Actual: " << actual_rects[i].ToString();
+      return false;
+    }
+  }
+
+  return true;
+}
+
+TEST(SimpleEnclosedRegionTest, Create) {
+  SimpleEnclosedRegion r1;
+  EXPECT_TRUE(r1.IsEmpty());
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(), r1));
+
+  SimpleEnclosedRegion r2(gfx::Rect(2, 3, 4, 5));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(2, 3, 4, 5), r2));
+
+  SimpleEnclosedRegion r3(2, 3, 4, 5);
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(2, 3, 4, 5), r3));
+
+  SimpleEnclosedRegion r4(4, 5);
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(4, 5), r4));
+
+  SimpleEnclosedRegion r5(Region(gfx::Rect(2, 3, 4, 5)));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(2, 3, 4, 5), r5));
+
+  SimpleEnclosedRegion r6(r5);
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(2, 3, 4, 5), r6));
+}
+
+TEST(SimpleEnclosedRegionTest, Assign) {
+  SimpleEnclosedRegion r;
+  EXPECT_TRUE(r.IsEmpty());
+
+  r = gfx::Rect(2, 3, 4, 5);
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(2, 3, 4, 5), r));
+
+  r = SimpleEnclosedRegion(3, 4, 5, 6);
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(3, 4, 5, 6), r));
+}
+
+TEST(SimpleEnclosedRegionTest, Clear) {
+  SimpleEnclosedRegion r(1, 2, 3, 4);
+  EXPECT_FALSE(r.IsEmpty());
+  r.Clear();
+  EXPECT_TRUE(r.IsEmpty());
+}
+
+TEST(SimpleEnclosedRegionTest, GetRegionComplexity) {
+  SimpleEnclosedRegion empty;
+  EXPECT_EQ(0u, empty.GetRegionComplexity());
+
+  SimpleEnclosedRegion stuff;
+  stuff.Union(gfx::Rect(1, 2, 3, 4));
+  EXPECT_EQ(1u, stuff.GetRegionComplexity());
+
+  // The SimpleEnclosedRegion only holds up to 1 rect.
+  stuff.Union(gfx::Rect(5, 6, 7, 8));
+  EXPECT_EQ(1u, stuff.GetRegionComplexity());
+}
+
+TEST(SimpleEnclosedRegionTest, Contains) {
+  SimpleEnclosedRegion r(1, 2, 5, 6);
+
+  EXPECT_FALSE(r.Contains(gfx::Point(0, 2)));
+  EXPECT_FALSE(r.Contains(gfx::Point(1, 1)));
+  EXPECT_TRUE(r.Contains(gfx::Point(1, 2)));
+
+  EXPECT_FALSE(r.Contains(gfx::Point(6, 2)));
+  EXPECT_FALSE(r.Contains(gfx::Point(5, 1)));
+  EXPECT_TRUE(r.Contains(gfx::Point(5, 2)));
+
+  EXPECT_FALSE(r.Contains(gfx::Point(0, 7)));
+  EXPECT_FALSE(r.Contains(gfx::Point(1, 8)));
+  EXPECT_TRUE(r.Contains(gfx::Point(1, 7)));
+
+  EXPECT_FALSE(r.Contains(gfx::Point(6, 7)));
+  EXPECT_FALSE(r.Contains(gfx::Point(5, 8)));
+  EXPECT_TRUE(r.Contains(gfx::Point(5, 7)));
+
+  EXPECT_FALSE(r.Contains(gfx::Rect(0, 2, 1, 1)));
+  EXPECT_FALSE(r.Contains(gfx::Rect(1, 1, 1, 1)));
+  EXPECT_TRUE(r.Contains(gfx::Rect(1, 2, 1, 1)));
+  EXPECT_FALSE(r.Contains(gfx::Rect(0, 1, 2, 2)));
+
+  EXPECT_FALSE(r.Contains(gfx::Rect(6, 2, 1, 1)));
+  EXPECT_FALSE(r.Contains(gfx::Rect(5, 1, 1, 1)));
+  EXPECT_TRUE(r.Contains(gfx::Rect(5, 2, 1, 1)));
+  EXPECT_FALSE(r.Contains(gfx::Rect(5, 1, 2, 2)));
+
+  EXPECT_FALSE(r.Contains(gfx::Rect(0, 7, 1, 1)));
+  EXPECT_FALSE(r.Contains(gfx::Rect(1, 8, 1, 1)));
+  EXPECT_TRUE(r.Contains(gfx::Rect(1, 7, 1, 1)));
+  EXPECT_FALSE(r.Contains(gfx::Rect(0, 7, 2, 2)));
+
+  EXPECT_FALSE(r.Contains(gfx::Rect(6, 7, 1, 1)));
+  EXPECT_FALSE(r.Contains(gfx::Rect(5, 8, 1, 1)));
+  EXPECT_TRUE(r.Contains(gfx::Rect(5, 7, 1, 1)));
+  EXPECT_FALSE(r.Contains(gfx::Rect(5, 7, 2, 2)));
+
+  gfx::Rect q(1, 2, 5, 6);
+  EXPECT_TRUE(r.Contains(q)) << q.ToString();
+  q.Inset(-1, 0, 0, 0);
+  EXPECT_FALSE(r.Contains(q)) << q.ToString();
+  q.Inset(1, -1, 0, 0);
+  EXPECT_FALSE(r.Contains(q)) << q.ToString();
+  q.Inset(0, 1, -1, 0);
+  EXPECT_FALSE(r.Contains(q)) << q.ToString();
+  q.Inset(0, 0, 1, -1);
+  EXPECT_FALSE(r.Contains(q)) << q.ToString();
+
+  q.Inset(1, 0, 0, 1);
+  EXPECT_TRUE(r.Contains(q)) << q.ToString();
+  q.Inset(-1, 1, 0, 0);
+  EXPECT_TRUE(r.Contains(q)) << q.ToString();
+  q.Inset(0, -1, 1, 0);
+  EXPECT_TRUE(r.Contains(q)) << q.ToString();
+  q.Inset(0, 0, -1, 1);
+  EXPECT_TRUE(r.Contains(q)) << q.ToString();
+
+  EXPECT_FALSE(r.Contains(SimpleEnclosedRegion(0, 2, 1, 1)));
+  EXPECT_FALSE(r.Contains(SimpleEnclosedRegion(1, 1, 1, 1)));
+  EXPECT_TRUE(r.Contains(SimpleEnclosedRegion(1, 2, 1, 1)));
+  EXPECT_FALSE(r.Contains(SimpleEnclosedRegion(0, 1, 2, 2)));
+
+  EXPECT_FALSE(r.Contains(SimpleEnclosedRegion(6, 2, 1, 1)));
+  EXPECT_FALSE(r.Contains(SimpleEnclosedRegion(5, 1, 1, 1)));
+  EXPECT_TRUE(r.Contains(SimpleEnclosedRegion(5, 2, 1, 1)));
+  EXPECT_FALSE(r.Contains(SimpleEnclosedRegion(5, 1, 2, 2)));
+
+  EXPECT_FALSE(r.Contains(SimpleEnclosedRegion(0, 7, 1, 1)));
+  EXPECT_FALSE(r.Contains(SimpleEnclosedRegion(1, 8, 1, 1)));
+  EXPECT_TRUE(r.Contains(SimpleEnclosedRegion(1, 7, 1, 1)));
+  EXPECT_FALSE(r.Contains(SimpleEnclosedRegion(0, 7, 2, 2)));
+
+  EXPECT_FALSE(r.Contains(SimpleEnclosedRegion(6, 7, 1, 1)));
+  EXPECT_FALSE(r.Contains(SimpleEnclosedRegion(5, 8, 1, 1)));
+  EXPECT_TRUE(r.Contains(SimpleEnclosedRegion(5, 7, 1, 1)));
+  EXPECT_FALSE(r.Contains(SimpleEnclosedRegion(5, 7, 2, 2)));
+
+  q = gfx::Rect(1, 2, 5, 6);
+  EXPECT_TRUE(r.Contains(SimpleEnclosedRegion(q))) << q.ToString();
+  q.Inset(-1, 0, 0, 0);
+  EXPECT_FALSE(r.Contains(SimpleEnclosedRegion(q))) << q.ToString();
+  q.Inset(1, -1, 0, 0);
+  EXPECT_FALSE(r.Contains(SimpleEnclosedRegion(q))) << q.ToString();
+  q.Inset(0, 1, -1, 0);
+  EXPECT_FALSE(r.Contains(SimpleEnclosedRegion(q))) << q.ToString();
+  q.Inset(0, 0, 1, -1);
+  EXPECT_FALSE(r.Contains(SimpleEnclosedRegion(q))) << q.ToString();
+
+  q.Inset(1, 0, 0, 1);
+  EXPECT_TRUE(r.Contains(SimpleEnclosedRegion(q))) << q.ToString();
+  q.Inset(-1, 1, 0, 0);
+  EXPECT_TRUE(r.Contains(SimpleEnclosedRegion(q))) << q.ToString();
+  q.Inset(0, -1, 1, 0);
+  EXPECT_TRUE(r.Contains(SimpleEnclosedRegion(q))) << q.ToString();
+  q.Inset(0, 0, -1, 1);
+  EXPECT_TRUE(r.Contains(SimpleEnclosedRegion(q))) << q.ToString();
+}
+
+TEST(SimpleEnclosedRegionTest, Intersects) {
+  SimpleEnclosedRegion r(1, 2, 5, 6);
+
+  EXPECT_FALSE(r.Intersects(gfx::Rect(0, 2, 1, 1)));
+  EXPECT_FALSE(r.Intersects(gfx::Rect(1, 1, 1, 1)));
+  EXPECT_TRUE(r.Intersects(gfx::Rect(1, 2, 1, 1)));
+  EXPECT_TRUE(r.Intersects(gfx::Rect(0, 1, 2, 2)));
+
+  EXPECT_FALSE(r.Intersects(gfx::Rect(6, 2, 1, 1)));
+  EXPECT_FALSE(r.Intersects(gfx::Rect(5, 1, 1, 1)));
+  EXPECT_TRUE(r.Intersects(gfx::Rect(5, 2, 1, 1)));
+  EXPECT_TRUE(r.Intersects(gfx::Rect(5, 1, 2, 2)));
+
+  EXPECT_FALSE(r.Intersects(gfx::Rect(0, 7, 1, 1)));
+  EXPECT_FALSE(r.Intersects(gfx::Rect(1, 8, 1, 1)));
+  EXPECT_TRUE(r.Intersects(gfx::Rect(1, 7, 1, 1)));
+  EXPECT_TRUE(r.Intersects(gfx::Rect(0, 7, 2, 2)));
+
+  EXPECT_FALSE(r.Intersects(gfx::Rect(6, 7, 1, 1)));
+  EXPECT_FALSE(r.Intersects(gfx::Rect(5, 8, 1, 1)));
+  EXPECT_TRUE(r.Intersects(gfx::Rect(5, 7, 1, 1)));
+  EXPECT_TRUE(r.Intersects(gfx::Rect(5, 7, 2, 2)));
+
+  gfx::Rect q(1, 2, 5, 6);
+  EXPECT_TRUE(r.Intersects(q)) << q.ToString();
+  q.Inset(-1, 0, 0, 0);
+  EXPECT_TRUE(r.Intersects(q)) << q.ToString();
+  q.Inset(1, -1, 0, 0);
+  EXPECT_TRUE(r.Intersects(q)) << q.ToString();
+  q.Inset(0, 1, -1, 0);
+  EXPECT_TRUE(r.Intersects(q)) << q.ToString();
+  q.Inset(0, 0, 1, -1);
+  EXPECT_TRUE(r.Intersects(q)) << q.ToString();
+
+  q.Inset(1, 0, 0, 1);
+  EXPECT_TRUE(r.Intersects(q)) << q.ToString();
+  q.Inset(-1, 1, 0, 0);
+  EXPECT_TRUE(r.Intersects(q)) << q.ToString();
+  q.Inset(0, -1, 1, 0);
+  EXPECT_TRUE(r.Intersects(q)) << q.ToString();
+  q.Inset(0, 0, -1, 1);
+  EXPECT_TRUE(r.Intersects(q)) << q.ToString();
+
+  EXPECT_FALSE(r.Intersects(SimpleEnclosedRegion(0, 2, 1, 1)));
+  EXPECT_FALSE(r.Intersects(SimpleEnclosedRegion(1, 1, 1, 1)));
+  EXPECT_TRUE(r.Intersects(SimpleEnclosedRegion(1, 2, 1, 1)));
+  EXPECT_TRUE(r.Intersects(SimpleEnclosedRegion(0, 1, 2, 2)));
+
+  EXPECT_FALSE(r.Intersects(SimpleEnclosedRegion(6, 2, 1, 1)));
+  EXPECT_FALSE(r.Intersects(SimpleEnclosedRegion(5, 1, 1, 1)));
+  EXPECT_TRUE(r.Intersects(SimpleEnclosedRegion(5, 2, 1, 1)));
+  EXPECT_TRUE(r.Intersects(SimpleEnclosedRegion(5, 1, 2, 2)));
+
+  EXPECT_FALSE(r.Intersects(SimpleEnclosedRegion(0, 7, 1, 1)));
+  EXPECT_FALSE(r.Intersects(SimpleEnclosedRegion(1, 8, 1, 1)));
+  EXPECT_TRUE(r.Intersects(SimpleEnclosedRegion(1, 7, 1, 1)));
+  EXPECT_TRUE(r.Intersects(SimpleEnclosedRegion(0, 7, 2, 2)));
+
+  EXPECT_FALSE(r.Intersects(SimpleEnclosedRegion(6, 7, 1, 1)));
+  EXPECT_FALSE(r.Intersects(SimpleEnclosedRegion(5, 8, 1, 1)));
+  EXPECT_TRUE(r.Intersects(SimpleEnclosedRegion(5, 7, 1, 1)));
+  EXPECT_TRUE(r.Intersects(SimpleEnclosedRegion(5, 7, 2, 2)));
+
+  q = gfx::Rect(1, 2, 5, 6);
+  EXPECT_TRUE(r.Intersects(SimpleEnclosedRegion(q))) << q.ToString();
+  q.Inset(-1, 0, 0, 0);
+  EXPECT_TRUE(r.Intersects(SimpleEnclosedRegion(q))) << q.ToString();
+  q.Inset(1, -1, 0, 0);
+  EXPECT_TRUE(r.Intersects(SimpleEnclosedRegion(q))) << q.ToString();
+  q.Inset(0, 1, -1, 0);
+  EXPECT_TRUE(r.Intersects(SimpleEnclosedRegion(q))) << q.ToString();
+  q.Inset(0, 0, 1, -1);
+  EXPECT_TRUE(r.Intersects(SimpleEnclosedRegion(q))) << q.ToString();
+
+  q.Inset(1, 0, 0, 1);
+  EXPECT_TRUE(r.Intersects(SimpleEnclosedRegion(q))) << q.ToString();
+  q.Inset(-1, 1, 0, 0);
+  EXPECT_TRUE(r.Intersects(SimpleEnclosedRegion(q))) << q.ToString();
+  q.Inset(0, -1, 1, 0);
+  EXPECT_TRUE(r.Intersects(SimpleEnclosedRegion(q))) << q.ToString();
+  q.Inset(0, 0, -1, 1);
+  EXPECT_TRUE(r.Intersects(SimpleEnclosedRegion(q))) << q.ToString();
+}
+
+TEST(SimpleEnclosedRegionTest, Equals) {
+  SimpleEnclosedRegion r(1, 2, 3, 4);
+  EXPECT_TRUE(r.Equals(SimpleEnclosedRegion(1, 2, 3, 4)));
+  EXPECT_FALSE(r.Equals(SimpleEnclosedRegion(2, 2, 3, 4)));
+  EXPECT_FALSE(r.Equals(SimpleEnclosedRegion(1, 3, 3, 4)));
+  EXPECT_FALSE(r.Equals(SimpleEnclosedRegion(1, 2, 4, 4)));
+  EXPECT_FALSE(r.Equals(SimpleEnclosedRegion(1, 2, 3, 5)));
+  EXPECT_FALSE(r.Equals(SimpleEnclosedRegion(2, 2, 2, 4)));
+  EXPECT_FALSE(r.Equals(SimpleEnclosedRegion(1, 3, 3, 3)));
+}
+
+TEST(SimpleEnclosedRegionTest, Bounds) {
+  SimpleEnclosedRegion r;
+  EXPECT_EQ(gfx::Rect(), r.bounds());
+  r = gfx::Rect(3, 4, 5, 6);
+  EXPECT_EQ(gfx::Rect(3, 4, 5, 6), r.bounds());
+  r.Union(gfx::Rect(1, 2, 12, 13));
+  EXPECT_EQ(gfx::Rect(1, 2, 12, 13), r.bounds());
+}
+
+TEST(SimpleEnclosedRegionTest, GetRect) {
+  SimpleEnclosedRegion r(3, 4, 5, 6);
+  EXPECT_EQ(gfx::Rect(3, 4, 5, 6), r.GetRect(0));
+  r.Union(gfx::Rect(1, 2, 12, 13));
+  EXPECT_EQ(gfx::Rect(1, 2, 12, 13), r.GetRect(0));
+}
+
+TEST(SimpleEnclosedRegionTest, Union) {
+  SimpleEnclosedRegion r;
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(), r));
+
+  // Empty Union anything = anything.
+  r.Union(gfx::Rect(4, 5, 6, 7));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(4, 5, 6, 7), r));
+
+  // Anything Union empty = anything.
+  r.Union(gfx::Rect());
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(4, 5, 6, 7), r));
+
+  // Anything Union contained rect = Anything.
+  r.Union(gfx::Rect(5, 6, 4, 5));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(4, 5, 6, 7), r));
+
+  // Anything Union containing rect = containing rect.
+  r.Union(gfx::Rect(2, 3, 8, 9));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(2, 3, 8, 9), r));
+  r.Union(gfx::Rect(2, 3, 9, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(2, 3, 9, 10), r));
+
+  // Union with a smaller disjoint rect is ignored.
+  r.Union(gfx::Rect(20, 21, 9, 9));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(2, 3, 9, 10), r));
+
+  // Union with a smaller overlapping rect is ignored.
+  r.Union(gfx::Rect(3, 4, 9, 9));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(2, 3, 9, 10), r));
+
+  // Union with an equal sized rect can be either one.
+  r.Union(gfx::Rect(4, 4, 9, 10));
+  EXPECT_EQ(1u, r.GetRegionComplexity());
+  EXPECT_TRUE(r.bounds() == gfx::Rect(2, 3, 9, 10) ||
+              r.bounds() == gfx::Rect(4, 4, 9, 10));
+
+  // Union with a larger disjoint rect is taken.
+  r.Union(gfx::Rect(20, 21, 12, 13));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(20, 21, 12, 13), r));
+
+  // Union with a larger overlapping rect is taken.
+  r.Union(gfx::Rect(19, 19, 12, 14));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(19, 19, 12, 14), r));
+
+  // True also when the rect covers one edge of the existing region.
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Union(gfx::Rect(12, 7, 9, 16));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(12, 7, 9, 16), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Union(gfx::Rect(9, 7, 9, 16));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(9, 7, 9, 16), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Union(gfx::Rect(7, 12, 16, 9));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(7, 12, 16, 9), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Union(gfx::Rect(7, 9, 16, 9));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(7, 9, 16, 9), r));
+
+  // But if the existing region can be expanded to make a larger rect, then it
+  // will. Union area is 9*12 = 108. By merging, we make a rect with an area of
+  // 10*11 = 110. The resulting rect is expanded as far as possible while
+  // remaining enclosed in the Union.
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Union(gfx::Rect(12, 9, 9, 12));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 11, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Union(gfx::Rect(9, 9, 9, 12));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(9, 10, 11, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Union(gfx::Rect(9, 12, 12, 9));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 10, 11), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Union(gfx::Rect(9, 9, 12, 9));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 9, 10, 11), r));
+
+  r = gfx::Rect(12, 9, 9, 12);
+  r.Union(gfx::Rect(10, 10, 10, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 11, 10), r));
+
+  r = gfx::Rect(9, 9, 9, 12);
+  r.Union(gfx::Rect(10, 10, 10, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(9, 10, 11, 10), r));
+
+  r = gfx::Rect(9, 12, 12, 9);
+  r.Union(gfx::Rect(10, 10, 10, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 10, 11), r));
+
+  r = gfx::Rect(9, 9, 12, 9);
+  r.Union(gfx::Rect(10, 10, 10, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 9, 10, 11), r));
+}
+
+TEST(SimpleEnclosedRegionTest, Subtract) {
+  SimpleEnclosedRegion r;
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(), r));
+
+  // Empty Subtract anything = empty.
+  r.Subtract(gfx::Rect(4, 5, 6, 7));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(), r));
+
+  // Subtracting an enclosing rect = empty.
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(10, 10, 10, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(9, 9, 12, 12));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(), r));
+
+  // Subtracting a rect that covers one side of the region will shrink that
+  // side.
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(18, 10, 10, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 8, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(18, 8, 10, 14));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 8, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(10, 18, 10, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 10, 8), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(8, 18, 14, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 10, 8), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(2, 10, 10, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(12, 10, 8, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(2, 8, 10, 14));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(12, 10, 8, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(10, 2, 10, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 12, 10, 8), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(8, 2, 14, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 12, 10, 8), r));
+
+  // Subtracting a rect that does not cover a full side will still shrink that
+  // side.
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(18, 12, 10, 8));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 8, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(18, 12, 10, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 8, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(12, 18, 8, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 10, 8), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(12, 18, 10, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 10, 8), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(2, 12, 10, 8));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(12, 10, 8, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(2, 12, 10, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(12, 10, 8, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(12, 2, 8, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 12, 10, 8), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(12, 2, 10, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 12, 10, 8), r));
+
+  // Subtracting a rect inside the region will make it choose the larger result.
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(11, 11, 7, 8));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(18, 10, 2, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(11, 11, 8, 7));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 18, 10, 2), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(12, 11, 7, 8));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 2, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(11, 12, 8, 7));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 10, 2), r));
+
+  // Subtracting a rect that cuts the region in two will choose the larger side.
+  // Here it's the top side.
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(10, 14, 10, 3));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 10, 4), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(0, 14, 30, 3));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 10, 4), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(10, 14, 8, 3));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 10, 4), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(0, 14, 18, 3));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 10, 4), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(12, 14, 18, 3));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 10, 4), r));
+
+  // Here it's the bottom side.
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(10, 13, 10, 3));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 16, 10, 4), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(0, 13, 30, 3));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 16, 10, 4), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(10, 13, 8, 3));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 16, 10, 4), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(0, 13, 18, 3));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 16, 10, 4), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(12, 13, 18, 3));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 16, 10, 4), r));
+
+  // Here it's the left side.
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(14, 10, 3, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 4, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(14, 10, 3, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 4, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(14, 10, 3, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 4, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(14, 10, 3, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 4, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(14, 10, 3, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 4, 10), r));
+
+  // Here it's the right side.
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(13, 10, 3, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(16, 10, 4, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(13, 10, 3, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(16, 10, 4, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(13, 10, 3, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(16, 10, 4, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(13, 10, 3, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(16, 10, 4, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(13, 10, 3, 10));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(16, 10, 4, 10), r));
+
+  // Subtracting a rect that leaves three possible choices will choose the
+  // larger.
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(10, 14, 7, 3));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 10, 4), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(10, 14, 5, 3));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(15, 10, 5, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(13, 14, 7, 3));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 10, 4), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(15, 14, 5, 3));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 5, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(14, 10, 3, 7));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 4, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(14, 10, 3, 5));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 15, 10, 5), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(14, 13, 3, 7));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 4, 10), r));
+
+  r = gfx::Rect(10, 10, 10, 10);
+  r.Subtract(gfx::Rect(14, 15, 3, 5));
+  EXPECT_TRUE(ExpectRegionEq(gfx::Rect(10, 10, 10, 5), r));
+}
+
+}  // namespace
+}  // namespace cc