title: Chrome CustomTabs CustomTabsCallback onPostMessage not called
body: <p>I'm trying to work with the Chrome CustomTabs on Android, but I have a problem about use of CustomTabsCallback.
  So, I searched on the web some examples or documentation to implement in my code, but I unfortunatelly I did not find anything...
  <br>I need to receive a postMessage sent by the hosted web page and read the content inside it. The postMessage was sent using "*" as origin, but I don't think that's the real problem.</p>
  
  <p>Here my code:</p>
  
  <pre><code>CustomTabsClient.bindCustomTabsService(context, CUSTOM_TAB_PACKAGE_NAME, new CustomTabsServiceConnection() {
          @Override
          public void onCustomTabsServiceConnected(ComponentName name, CustomTabsClient client) {
              mClient = client;
              mClient.warmup(0);
              CustomTabsSession session = mClient.newSession(new CustomTabsCallback() {
                  @Override
                  public void onPostMessage(String message, Bundle extras) {
                      // Here the method not called by CustomTabs
                      super.onPostMessage(message, extras);
                  }
  
                  @Override
                  public void onMessageChannelReady(Bundle extras) {
                      super.onMessageChannelReady(extras);
                  }
  
                  @Override
                  public void onNavigationEvent(int navigationEvent, Bundle extras) {
                      super.onNavigationEvent(navigationEvent, extras);
                  }
              });
              session.mayLaunchUrl(uri, null, null);
              CustomTabsIntent.Builder builder = new CustomTabsIntent.Builder(session);
              CustomTabsIntent customTabsIntent = builder.build();
              customTabsIntent.launchUrl(context, uri);
          }
  
          @Override
          public void onServiceDisconnected(ComponentName name) {
              mClient = null;
          }
      });
  </code></pre>
  
  <p>I accept all suggestions, it's making me crazy.</p>
  
  <p>Thanks in advance.</p>