Merge "Improve documentation for custome token."

     * @param authTokenType the type of auth token to retrieve after adding the account, may be null

     * @param requiredFeatures a String array of authenticator-specific features that the added

     * account must support, may be null

     * @param options a Bundle of authenticator-specific options, may be null

     * @param options a Bundle of authenticator-specific options. It always contains

     * {@link AccountManager#KEY_CALLER_PID} and {@link AccountManager#KEY_CALLER_UID}

     * fields which will let authenticator know the identity of the caller.

     * @return a Bundle result or null if the result is to be returned via the response. The result

     * will contain either:

     * <ul>

     * addition {@link AbstractAccountAuthenticator} implementations that declare themselves

     * {@code android:customTokens=true} may also provide a non-negative {@link

     * #KEY_CUSTOM_TOKEN_EXPIRY} long value containing the expiration timestamp of the expiration

     * time (in millis since the unix epoch).

     * time (in millis since the unix epoch), tokens will be cached in memory based on

     * application's packageName/signature for however long that was specified.

     * <p>

     * Implementers should assume that tokens will be cached on the basis of account and

     * authTokenType. The system may ignore the contents of the supplied options Bundle when

     * determining to re-use a cached token. Furthermore, implementers should assume a supplied

     * expiration time will be treated as non-binding advice.

     * <p>

     * Finally, note that for android:customTokens=false authenticators, tokens are cached

     * Finally, note that for {@code android:customTokens=false} authenticators, tokens are cached

     * indefinitely until some client calls {@link

     * AccountManager#invalidateAuthToken(String,String)}.

     *

     * @param response to send the result back to the AccountManager, will never be null

     * @param account the account whose credentials are to be retrieved, will never be null

     * @param authTokenType the type of auth token to retrieve, will never be null

     * @param options a Bundle of authenticator-specific options, may be null

     * @param options a Bundle of authenticator-specific options. It always contains

     * {@link AccountManager#KEY_CALLER_PID} and {@link AccountManager#KEY_CALLER_UID}

     * fields which will let authenticator know the identity of the caller.

     * @return a Bundle result or null if the result is to be returned via the response.

     * @throws NetworkErrorException if the authenticator could not honor the request due to a

     * network error

    public static final String KEY_LAST_AUTHENTICATED_TIME = "lastAuthenticatedTime";

    /**

     * Authenticators using 'customTokens' option will also get the UID of the

     * caller

     * The UID of caller app.

     */

    public static final String KEY_CALLER_UID = "callerUid";

    /**

     * The process id of caller app.

     */

    public static final String KEY_CALLER_PID = "callerPid";

    /**