I.MX6 默认打开 USB adb

/*****************************************************************************
 *                        I.MX6 默认打开 USB adb
 * 声明：
 *     在调试android的时候，尤其是前期，可能我们没有Touch，这样使用adb显得
 * 力不从心，因为它会弹个对话框来，可你有按不了，于是默认打开adb就成了需求。
 *
 *                                          2016-1-20 深圳 南山平山村 曾剑锋
 ****************************************************************************/

一、参考文章：
    飞思卡尔 imx6 android 调试环境搭建
        http://www.wjxfpf.com/2015/10/590190.html
    Android 4.2.2 开机默认开启USB调试
        http://blog.csdn.net/zhujm320/article/details/37914487
    默认打开USB调试功能
        http://blog.csdn.net/pfgmylove/article/details/16985159

二、解决方案：
    1. cat frameworks/base/services/java/com/android/server/usb/UsbDeviceManager.java
        ......
        public void systemReady() {
            if (DEBUG) Slog.d(TAG, "systemReady");
            mNotificationManager = (NotificationManager)
                mContext.getSystemService(Context.NOTIFICATION_SERVICE);

            // We do not show the USB notification if the primary volume supports mass storage.
            // The legacy mass storage UI will be used instead.
            boolean massStorageSupported = false;
            final StorageManager storageManager = StorageManager.from(mContext);
            final StorageVolume primary = storageManager.getPrimaryVolume();
            massStorageSupported = primary != null && primary.allowMassStorage();
            mUseUsbNotification = !massStorageSupported;


            // make sure the ADB_ENABLED setting value matches the current state
            //Settings.Global.putInt(mContentResolver, Settings.Global.ADB_ENABLED, mAdbEnabled ? 1 : 0);
            Settings.Global.putInt(mContentResolver, Settings.Global.ADB_ENABLED, 1); 
            mHandler.sendEmptyMessage(MSG_SYSTEM_READY);
        }
        ......
    2. cat /init.rc
        ......
        #  Enable adb security for JB4.2.2
            setprop ro.adb.secure 0
        ......