title: Topic is created on cloud pub/sub but unable to create watch on that topic
body: <p>I want to create watch on cloud pub/sub topic but unable to create it. For that I'm using the rest request</p>
  
  <pre><code>request_Req.post({
  
  url:'https://www.googleapis.com/gmail/v1/users/me/watch',
  headers:{
     'content-type': 'application/json',
     'Authorization': 'Bearer '+ access_token,
  },
  scope : [
      'https://mail.google.com/'
  ],
  
  'body': JSON.stringify({
      'topicName' : "/projects/ProjectId/topics/TopicId",
      'labelIds' : ["INBOX"] 
  });
  }),function(error, resp, body){
  
  });
  </code></pre>
  
  <p>But I'm getting the error message <code>Error sending test message to Cloud 
  PubSub/projects/ProjectID/topics/TopicId : Resource not found        resource=TopicId</code></p>