ui: Add methods to Rect classes to get points at each of the rect's corners.

ui/gfx/rect_unittest.cc

Index: ui/gfx/rect_unittest.cc
diff --git a/ui/gfx/rect_unittest.cc b/ui/gfx/rect_unittest.cc
index be1df46994f873087a6f39ad9df246179c21b01a..389fe8f6740559c0ca2b1fe83bba8d1efb6f3997 100644
--- a/ui/gfx/rect_unittest.cc
+++ b/ui/gfx/rect_unittest.cc
@@ -743,4 +743,19 @@ TEST(RectTest, Offset) {
   EXPECT_EQ(RectF(1.1f, 2.2f, 3.3f, 4.4f).ToString(), f.ToString());
 }
 
+TEST(RectTest, Corners) {
+  Rect i(1, 2, 3, 4);
+  RectF f(1.1f, 2.1f, 3.1f, 4.1f);
+
+  EXPECT_EQ(Point(1, 2).ToString(), i.TopLeft().ToString());
+  EXPECT_EQ(Point(4, 2).ToString(), i.TopRight().ToString());
+  EXPECT_EQ(Point(1, 6).ToString(), i.BottomLeft().ToString());
+  EXPECT_EQ(Point(4, 6).ToString(), i.BottomRight().ToString());
+
+  EXPECT_EQ(PointF(1.1f, 2.1f).ToString(), f.TopLeft().ToString());
+  EXPECT_EQ(PointF(4.2f, 2.1f).ToString(), f.TopRight().ToString());
+  EXPECT_EQ(PointF(1.1f, 6.2f).ToString(), f.BottomLeft().ToString());
+  EXPECT_EQ(PointF(4.2f, 6.2f).ToString(), f.BottomRight().ToString());
+}
+
 }  // namespace gfx