Add W3C encrypted-media tests

third_party/WebKit/LayoutTests/imported/wpt/encrypted-media/util/utf8.js

+if ( typeof TextEncoder !== "undefined" && typeof TextDecoder !== "undefined" )
+{
+    utf8encoder = new TextEncoder('utf-8');
+    utf8decoder = new TextDecoder('utf-8');
+}
+else
+{
+    utf8encoder = { encode: function( text )
+    {
+        var result = new Uint8Array(text.length);
+        for(var i = 0; i < text.length; i++) { result[i] = text.charCodeAt(i); }
+        return result;
+    } };
+
+    utf8decoder = { decode: function( buffer )
+    {
+        return String.fromCharCode.apply(null, new Uint8Array(buffer));
+    } };
+}
+
+toUtf8 = function( o ) { return utf8encoder.encode( JSON.stringify( o ) ); }
+fromUtf8 = function( t ) { return JSON.parse( utf8decoder.decode( t ) ); }