[Remoting Android] use HelpAndFeedback.launchFeedback to launch the feedback activity

remoting/android/java/src/org/chromium/chromoting/help/HelpAndFeedback.java

 // Copyright 2015 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.help;
 
 import android.app.Activity;
 
 /** Common interface for help-and-feedback implementations. */
 public interface HelpAndFeedback {
     /**
      * Launches a new activity for displaying a Help screen. The implementation will show
      * information depending on the context, and will allow the user to submit a Feedback
      * report. The implementation may also grab a screenshot, so the caller should take
      * any steps to prepare the display before calling this method (for example, closing
      * navigation drawers).
      * @param activity Parent activity of the Help screen.
      * @param helpContext String used by the implementation to show context-based help.
      */
     void launchHelp(Activity activity, HelpContext helpContext);
+
+    /**
+     * Launches a new activity for displaying the feedback screen. The implementation may grab
+     * a screenshot.
+     * @param activity Parent activity of the feedback screen.
+     */
+    void launchFeedback(Activity activity);
 }