按手机返回键退出，日志打印异常

使用华为的手机，按手机返回键时，总是打印异常信息，导致一些事件丢失，请看看是什么原因？
12-30 09:41:40.866 10669-10669/com.huawei.mcloud.m4.plugin W/cr_AwContents: Application attempted to call on a destroyed WebView
java.lang.Throwable
at org.chromium.android_webview.AwContents.isDestroyed(AwContents.java:1151)
at org.chromium.android_webview.AwContents.clearCache(AwContents.java:1864)
at com.android.webview.chromium.WebViewChromium.clearCache(WebViewChromium.java:1087)
at android.webkit.WebView.clearCache(WebView.java:1522)
at io.dcloud.common.adapter.ui.AdaWebview$1.execute(AdaWebview.java:315)
at io.dcloud.common.adapter.util.MessageHandler$1.handleMessage(MessageHandler.java:23)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:150)
at android.app.ActivityThread.main(ActivityThread.java:5546)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:794)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:684)
12-30 09:41:40.879 10669-10669/com.huawei.mcloud.m4.plugin W/cr_ScreenOrientation: Removing an inexistent observer!

                                                                               [ 12-30 09:41:41.264  3743: 3743 E/         ]  
                                                                               process stopped due to unexpected signal 13