Move visual rect unioning between paired items to cc::DisplayItemList.

cc/test/geometry_test_utils.h

Index: cc/test/geometry_test_utils.h
diff --git a/cc/test/geometry_test_utils.h b/cc/test/geometry_test_utils.h
index eee215ca14b6ef57e7f4d9f5750a36b67b02458d..6e015131fa7d676dd378130cc2ff279e10b9657a 100644
--- a/cc/test/geometry_test_utils.h
+++ b/cc/test/geometry_test_utils.h
@@ -21,6 +21,15 @@ namespace cc {
     EXPECT_FLOAT_EQ((expected).height(), (actual).height()); \
   } while (false)
 
+#define EXPECT_RECT_EQ(expected, actual)               \
+  do {                                                 \
+    const gfx::Rect& actualRect = actual;              \
+    EXPECT_EQ(expected.x(), actualRect.x());           \
+    EXPECT_EQ(expected.y(), actualRect.y());           \
+    EXPECT_EQ(expected.width(), actualRect.width());   \
+    EXPECT_EQ(expected.height(), actualRect.height()); \
+  } while (false)
+
 #define EXPECT_RECT_NEAR(expected, actual, abs_error)                 \
   do {                                                                \
     EXPECT_NEAR((expected).x(), (actual).x(), (abs_error));           \