Allow JSON messages to be returned for ClearKey.

LayoutTests/media/encrypted-media/encrypted-media-utils.js

Index: LayoutTests/media/encrypted-media/encrypted-media-utils.js
diff --git a/LayoutTests/media/encrypted-media/encrypted-media-utils.js b/LayoutTests/media/encrypted-media/encrypted-media-utils.js
index ed59afe2881e47190e86f15365f91b7ab7d90c78..a91023926f119eaab05070103c33f55359286d26 100644
--- a/LayoutTests/media/encrypted-media/encrypted-media-utils.js
+++ b/LayoutTests/media/encrypted-media/encrypted-media-utils.js
@@ -123,3 +123,24 @@ function forceTestFailureFromPromise(test, error, message)
     test.force_timeout();
     test.done();
 }
+
+function extractSingleKeyIdFromMessage(message)
+{
+    try {
+        var json = JSON.parse(String.fromCharCode.apply(null, new Uint8Array(message)));
+        // Decode the first element of 'kids'.
+        // FIXME: Switch to base64url. See
+        // https://dvcs.w3.org/hg/html-media/raw-file/default/encrypted-media/encrypted-media.html#using-base64url
+        assert_equals(1, json.kids.length);
+        var decoded_key = atob(json.kids[0]);
+        // Convert to an Uint8Array and return it.
+        return stringToUint8Array(decoded_key);
+    }
+    catch (o) {
+        // Not valid JSON, so return message untouched as Uint8Array.
+        // This is for backwards compatibility.
+        // FIXME: Remove this once the code is switched to return JSON all
+        // the time.
+        return new Uint8Array(message);
+    }
+}