[webcrypto] Expose crypto.subtle to web workers.

LayoutTests/crypto/resources/common.js

 // Verifies that the given "bytes" holds the same value as "expectedHexString".
 // "bytes" can be anything recognized by "bytesToHexString()".
 function bytesShouldMatchHexString(testDescription, expectedHexString, bytes)
 {
     expectedHexString = "[" + expectedHexString.toLowerCase() + "]";
     var actualHexString = "[" + bytesToHexString(bytes) + "]";
 
     if (actualHexString === expectedHexString) {
         debug("PASS: " + testDescription + " should be " + expectedHexString + " and was");
     } else {
@@ skipping 42 matching lines @@
 function asciiToUint8Array(str)
 {
     var chars = [];
     for (var i = 0; i < str.length; ++i)
         chars.push(str.charCodeAt(i));
     return new Uint8Array(chars);
 }
 
 function failAndFinishJSTest(error)
 {
-    testFailed(error);
+    testFailed('' + error);
     finishJSTest();
 }
 
 // Returns a Promise for the cloned key.
 function cloneKey(key)
 {
     // Sending an object through a MessagePort implicitly clones it.
     // Use a single MessageChannel so requests complete in FIFO order.
     var self = cloneKey;
     if (!self.channel) {
@@ skipping 18 matching lines @@
     if (internals)
         debug("Serialized key bytes: " + bytesToHexString(internals.serializeObject(o)));
 }
 
 function shouldEvaluateAs(actual, expectedValue)
 {
     if (typeof expectedValue == "string")
         return shouldBeEqualToString(actual, expectedValue);
     return shouldEvaluateTo(actual, expectedValue);
 }