Import wpt/webmessaging tests

third_party/WebKit/LayoutTests/external/wpt/webmessaging/support/compare.js

+function sameDate(d1, d2) {
+  return (d1 instanceof Date && d2 instanceof Date && d1.valueOf() == d2.valueOf());
+}
+
+function sameRE(r1, r2) {
+  return (r1 instanceof RegExp && r2 instanceof RegExp && r1.toString() == r2.toString());
+}
+
+function assert_array_equals_(observed, expected, msg) {
+  if (observed.length == expected.length) {
+    for (var i = 0; i < observed.length; i++) {
+      if (observed[i] instanceof Date) {
+        observed[i] = sameDate(observed[i], expected[i]);
+        expected[i] = true;
+      } else if (observed[i] instanceof RegExp) {
+        observed[i] = sameRE(observed[i], expected[i]);
+        expected[i] = true;
+      }
+    }
+  }
+
+  assert_array_equals(observed, expected, msg);
+}
+
+function assert_object_equals_(observed, expected, msg) {
+  for (var p in observed) {
+    if (observed[p] instanceof Date) {
+      observed[p] = sameDate(observed[p], expected[p]);
+      expected[p] = true;
+    } else if (observed[p] instanceof RegExp) {
+      observed[p] = sameRE(observed[p], expected[p]);
+      expected[p] = true;
+    } else if (observed[p] instanceof Array || String(observed[p]) === '[object Object]') {
+      observed[p] = String(observed[p]) === String(expected[p]);
+      expected[p] = true;
+    }
+    assert_equals(observed[p], expected[p], msg);
+  }
+}