Move Java Blimp shell code to app subpackage

blimp/client/app/android/java/src/org/chromium/blimp/auth/TokenSource.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.blimp.auth;
-
-import android.content.Intent;
-
-import com.google.android.gms.common.ConnectionResult;
-
-/**
- * Interface for an object that can asynchronously retrieve and invalidate user authentication
- * tokens.
- */
-public interface TokenSource {
-    /**
-     * Used to get results of {@link TokenSource#getToken()} attempts.
-     */
-    public interface Callback {
-        /**
-         * A token was successfully received.
-         * @param token The token.
-         */
-        void onTokenReceived(String token);
-
-        /**
-         * A token was unable to be retrieved.
-         * @param isTransient Whether or not the failure is recoverable or not.
-         */
-        void onTokenUnavailable(boolean isTransient);
-
-        /**
-         * There is no selected user account on the device.  By triggering {@code intent} with a
-         * result (via {@link android.app.Activity#startActivityForResult(Intent, int)) the calling
-         * {@code android.app.Activity} can show an account chooser to the user.  The resulting
-         * {@link Intent} should be passed to the {@link TokenSource} via
-         * {@link TokenSource#onAccountSelected(Intent)}.
-         * @param intent The {@link Intent} to start to have the user select an account.
-         */
-        void onNeedsAccountToBeSelected(Intent intent);
-    }
-
-    /**
-     * Destroys all internal state and stops (if possible) any outstanding
-     * {@link TokenSource#getToken()} attempts.
-     */
-    void destroy();
-
-    /**
-     * TODO(dtrainor): Rework this to move the Account and Callback into getToken() (crbug/537728).
-     * Sets the {@link Callback} that will be notified of the results of {@link getToken()} calls.
-     * @param callback The {@link Callback} to notify.
-     */
-    void setCallback(Callback callback);
-
-    /**
-     * Starts off a process of getting an authentication token for the selected account for this
-     * application.  If this is called before finishing, it should cancel the outstanding request
-     * and start a new one.  See {@link Callback} for specific details of each possible callback
-     * outcome.
-     * - If no account is selected, {@link Callback#onNeedsAccountToBeSelected(Intent)} will be
-     * called.
-     * - If getting the token fails, {@link Callback#onTokenUnavailable(boolean)} will be called.
-     * - If getting the token is successful, {@link Callback#onTokenReceived(String)} will be
-     * called.
-     */
-    void getToken();
-
-    /**
-     * @return Whether or not this {@link TokenSource} is currently trying to retrieve a token.
-     */
-    boolean isRetrievingToken();
-
-    /**
-     * Notifies this {@link TokenSource} that the token it returned is invalid.  This won't
-     * automatically trigger another {@link #getToken()} attempt.
-     * @param token The token that is invalid and should be removed from the underlying token cache.
-     * @return      The result code of the attempted invalidation (see {@link ConnectionResult}.
-     */
-    int tokenIsInvalid(String token);
-
-    /**
-     * Notifies this {@link TokenSource} of a response from the {@link Intent} sent through
-     * {@link Callback#onNeedsAccountToBeSelected(Intent)}.  The selected account will be parsed and
-     * saved.  This won't automatically trigger another {@link #getToken()} attempt.
-     * @param data The response {@link Intent} data.
-     */
-    void onAccountSelected(Intent data);
-}