title: In-App Billing v3 restore purchase
body: <p>Right now I'm using inapp purchase v3, and I am able to buy an item.</p>
  
  <p>But when I've bought it, and I uninstall the app, clear Google Play data and remove the account (and then I log in again with same account), when I install that app again, my purchase history is empty. How do I restore it in v3?</p>
  
  <p>If I look at the code in IabHelper there is a function <code>queryPurchases</code>:</p>
  
  <pre><code>Bundle ownedItems = mService.getPurchases(3, mContext.getPackageName(),
                  itemType, continueToken);
  </code></pre>
  
  <p>but the first time, continueToken is null. Might that be the problem?</p>