Implement DataCue interface.

LayoutTests/media/video-test.js

Index: LayoutTests/media/video-test.js
diff --git a/LayoutTests/media/video-test.js b/LayoutTests/media/video-test.js
index e558c1db9a90094ddbfc71a27856c090e750edfb..3b1ba7555c68e281ea08422b901851f79cb4171f 100644
--- a/LayoutTests/media/video-test.js
+++ b/LayoutTests/media/video-test.js
@@ -88,6 +88,7 @@ function testExpected(testFuncString, expected, comparison)
         case '!=':  success = observed != expected; break;
         case '==': success = observed == expected; break;
         case '===': success = observed === expected; break;
+        case 'instanceof': success = observed instanceof expected; break;
     }
 
     reportExpected(success, testFuncString, comparison, expected, observed)
@@ -216,7 +217,7 @@ function testDOMException(testString, exceptionString)
         var exception = ex;
     }
     logResult(exception instanceof DOMException && exception.code === eval(exceptionString),
-        "TEST(" + testString + ") THROWS(" + exceptionString + ": " + exception.message + ")");
+        "TEST(" + testString + ") THROWS(" + exceptionString + ": " + (exception ? exception.message : undefined) + ")");

[philipj_slow, 2014/04/04 14:54:33]

Unrelated change?

[Brendan Long, 2014/04/04 15:07:22]

This was necessary to make the test not crash if it fails (previously, if no
exception was through, 'exception' would be undefined and 'exception.message'
would cause a crash). I changed this to make it easier to write the tests, but I
think it's reasonable to leave it in place. I can remove it if you don't think
it should be here though.

 }
 
 function testException(testString, exceptionString) {