Web MIDI: prepare to deprecate MIDIMessageEvent::receivedTime

third_party/WebKit/LayoutTests/webmidi/loopback-receive.html

Index: third_party/WebKit/LayoutTests/webmidi/loopback-receive.html
diff --git a/third_party/WebKit/LayoutTests/webmidi/loopback-receive.html b/third_party/WebKit/LayoutTests/webmidi/loopback-receive.html
index 9728155a3a70d1aa81c44e2be35522c4705aa1d1..c3f6b0f24161f5100ece95d5f5c6cdda74d7be53 100644
--- a/third_party/WebKit/LayoutTests/webmidi/loopback-receive.html
+++ b/third_party/WebKit/LayoutTests/webmidi/loopback-receive.html
@@ -43,6 +43,8 @@ function verifyData(e) {
     expected = testData[receiveCount];
     actual = e.data;
     shouldBe("actual", "expected");
+    midiMessageEvent = e;
+    shouldBeTrue("midiMessageEvent.receivedTime !== undefined");
     receiveCount++;
     if (receiveCount == testData.length)
         e.target.resolve();