android源码修改，实现长按电源键直接关机

private final Runnable mPowerLongPress = new Runnable() {
        @Override
        public void run() {
            // The context isn‘t read
            if (mLongPressOnPowerBehavior < 0) {
                mLongPressOnPowerBehavior = mContext.getResources().getInteger(
                        com.android.internal.R.integer.config_longPressOnPowerBehavior);
            }
            int resolvedBehavior = mLongPressOnPowerBehavior;
            if (FactoryTest.isLongPressOnPowerOffEnabled()) {
                resolvedBehavior = LONG_PRESS_POWER_SHUT_OFF_NO_CONFIRM;
            }
/*
            switch (resolvedBehavior) {
            case LONG_PRESS_POWER_NOTHING:
                break;
            case LONG_PRESS_POWER_GLOBAL_ACTIONS:
                mPowerKeyHandled = true;
                if (!performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false)) {
                    performAuditoryFeedbackForAccessibilityIfNeed();
                }
                sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
                showGlobalActionsDialog();
                break;
            case LONG_PRESS_POWER_SHUT_OFF:
            case LONG_PRESS_POWER_SHUT_OFF_NO_CONFIRM:
                mPowerKeyHandled = true;
                performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false);
                sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
                mWindowManagerFuncs.shutdown(resolvedBehavior == LONG_PRESS_POWER_SHUT_OFF);
                break;
            }
*/
            //注释掉上面的代码后，增加下面的代码
            mPowerKeyHandled = true;
            performHapticFeedbackLw(null, HapticFeedbackConstants.LONG_PRESS, false);
            sendCloseSystemWindows(SYSTEM_DIALOG_REASON_GLOBAL_ACTIONS);
            mWindowManagerFuncs.shutdown(false);//这里false代表不显示关机提示框，true未显示关机提示框
        }
    };