DevTools: Fix url assignment when renaming files in workspace

LayoutTests/http/tests/inspector/isolated-filesystem-test.js

Index: LayoutTests/http/tests/inspector/isolated-filesystem-test.js
diff --git a/LayoutTests/http/tests/inspector/isolated-filesystem-test.js b/LayoutTests/http/tests/inspector/isolated-filesystem-test.js
index 36ec9f33490aeb69057fad0e626769c1c2da4d33..cf8cebf73da513f8536087cbe979226fe97da768 100644
--- a/LayoutTests/http/tests/inspector/isolated-filesystem-test.js
+++ b/LayoutTests/http/tests/inspector/isolated-filesystem-test.js
@@ -57,6 +57,11 @@ MockIsolatedFileSystem.prototype = {
         this._innerRequestFilesRecursive();
     },
 
+    renameFile: function(filePath, newName, callback)
+    {
+        callback(true, newName);
+    },
+
     _innerRequestFilesRecursive: function()
     {
         if (!this._callback)