/** Loads url on the UI thread and blocks until onPageFinished is called. */
 protected void loadUrlSync(
     final AwContents awContents, CallbackHelper onPageFinishedHelper, final String url)
     throws Throwable {
   int currentCallCount = onPageFinishedHelper.getCallCount();
   loadUrlAsync(awContents, url);
   onPageFinishedHelper.waitForCallback(
       currentCallCount, 1, WAIT_TIMEOUT_SECONDS, TimeUnit.SECONDS);
 }
 protected void loadUrlSyncAndExpectError(
     final AwContents awContents,
     CallbackHelper onPageFinishedHelper,
     CallbackHelper onReceivedErrorHelper,
     final String url)
     throws Throwable {
   int onErrorCallCount = onReceivedErrorHelper.getCallCount();
   int onFinishedCallCount = onPageFinishedHelper.getCallCount();
   loadUrlAsync(awContents, url);
   onReceivedErrorHelper.waitForCallback(
       onErrorCallCount, 1, WAIT_TIMEOUT_SECONDS, TimeUnit.SECONDS);
   onPageFinishedHelper.waitForCallback(
       onFinishedCallCount, 1, WAIT_TIMEOUT_SECONDS, TimeUnit.SECONDS);
 }