ANR 超时时间定义
定义位置：ActivityManagerService.java 中定义
Broadcast ANR 时间为 10s：
// How long we allow a receiver to run before giving up on it.
static fianl int BROADCAST_TIMEOUT=10*1000；按键无响应 ANR 时间为 5s；
//how long we wait until we timeout on key dispatching.
static final int KEY_DISPATCHING_TIMEOUT=5*1000；