1、主要会用到如下这个类中的方法
InputManagerService：interceptKeyBeforeQueueing
WindowManagerCallbacks：interceptKeyBeforeQueueing
InputManagerCallback ：interceptKeyBeforeQueueing
WindowManagerPolicy : interceptKeyBeforeQueueing
PhoneWindowManager.java : interceptKeyBeforeQueueing

2、PhoneWindowManager Power键点击分析：

@Override
public int interceptKeyBeforeQueueing(KeyEvent event, int policyFlags) {
   
    final int keyCode