Fix Chromoting Android client crashed on launch

remoting/android/java/src/org/chromium/chromoting/Chromoting.java

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chromoting;
 
 import android.accounts.Account;
 import android.accounts.AccountManager;
 import android.accounts.AccountManagerCallback;
 import android.accounts.AccountManagerFuture;
 import android.accounts.AuthenticatorException;
 import android.accounts.OperationCanceledException;
 import android.annotation.SuppressLint;
 import android.app.ActionBar;
 import android.app.Activity;
 import android.app.AlertDialog;
 import android.app.ProgressDialog;
 import android.content.DialogInterface;
 import android.content.Intent;
 import android.content.SharedPreferences;
 import android.content.res.Configuration;
-import android.os.Build;
 import android.os.Bundle;
 import android.provider.Settings;
 import android.util.Log;
 import android.view.Menu;
 import android.view.MenuItem;
 import android.view.View;
 import android.widget.ArrayAdapter;
 import android.widget.ListView;
 import android.widget.Toast;
 
@@ skipping 357 matching lines @@
             explanation = getString(R.string.error_authentication_failed);
             Toast.makeText(this, explanation, Toast.LENGTH_LONG).show();
             setHostListProgressVisible(false);
         }
     }
 
     /**
      * Updates the infotext and host list display.
      */
     private void updateUi() {
-        mRefreshButton.setEnabled(mAccount != null);
-
+        if (mRefreshButton != null) {

[Lambros, 2014/06/02 17:07:22]

Looks like there's a race between updateUi() and onCreateOptionsMenu(). This is
the right fix here, but I wonder if we need to do anything in
onCreateOptionsMenu() to ensure the button is initially created in the right
state? Probably not, but worth checking anyway?

+            mRefreshButton.setEnabled(mAccount != null);
+        }
         ArrayAdapter<HostInfo> displayer = new HostListAdapter(this, R.layout.host, mHosts);
         Log.i("hostlist", "About to populate host list display");
         mHostListView.setAdapter(displayer);
     }
 
     @Override
     public void onConnectionState(JniInterface.ConnectionListener.State state,
             JniInterface.ConnectionListener.Error error) {
         boolean dismissProgress = false;
         switch (state) {
@@ skipping 28 matching lines @@
                 // Unreachable, but required by Google Java style and findbugs.
                 assert false : "Unreached";
         }
 
         if (dismissProgress && mProgressIndicator != null) {
             mProgressIndicator.dismiss();
             mProgressIndicator = null;
         }
     }
 }