Don't poke user activity when unplugging unless screen is already on.

                    // treat plugging and unplugging the devices as a user activity.

                    // users find it disconcerting when they unplug the device

                    // and it shuts off right away.

                    // to avoid turning on the screen when unplugging, we only trigger

                    // user activity when screen was already on.

                    // temporarily set mUserActivityAllowed to true so this will work

                    // even when the keyguard is on.

                    synchronized (mLocks) {

                        if (!wasPowered || (mPowerState & SCREEN_ON_BIT) != 0) {

                            forceUserActivityLocked();

                        }

                    }

                }

            }

        }

    }

    private final class BootCompletedReceiver extends BroadcastReceiver {

        @Override