Youtube_player_flutter: El método deactivate () da error

Cuando navego por una página que contiene un reproductor de video a otra página, aparece un error en _controller.pause(); línea.

void desactivar() {
_controlador.pausa();
super.desactivar();
}

Registro de eventos a continuación:

W/ScreenOrientationListener(17293): Eliminando un observador inexistente.
W/chromium(17293): [ADVERTENCIA:aw_contents.cc(315)] SP>>> Destruir
I/chromium(17293): [INFO:synchronous_compositor_impl.cc(111)] [SynchronousCompositorImpl::SetClient] [0x0000007f359b5ec0]
I/MediaCodec(17293): [lanzamiento]línea:383 [OMX.google.opus.decoder]+++
I/ACodec (17293): índice de puerto freeBuffersOnPort 0
I/ACodec (17293): freeBuffersOnPort portIndex 1
I/MediaCodec(17293): [onMessageReceived]línea:1268 [OMX.google.opus.decoder][what=kWhatShutdownCompleted][state 10][msg='AMessage(what = 'codc', target = 2) = {
I/MediaCodec(17293): int32_t qué = 1935896429
I/MediaCodec(17293): }' ]
I/MediaCodec(17293): [~MediaCodec]línea:205 [][mState 0]+++
I/MediaCodec(17293): [lanzamiento]línea:383 [OMX.MTK.VIDEO.DECODER.VP9]+++
I/ACodec (17293): índice de puerto freeBuffersOnPort 0
I/ACodec (17293): freeBuffersOnPort portIndex 1
I/MediaCodec(17293): [onMessageReceived]line:1268 [OMX.MTK.VIDEO.DECODER.VP9][what=kWhatShutdownCompleted][state 10][msg='AMessage(what = 'codc', target = 5) = {
I/MediaCodec(17293): int32_t qué = 1935896429
I/MediaCodec(17293): }' ]
I/MediaCodec(17293): [~MediaCodec]línea:205 [][mState 0]+++
E/flutter (17293): [ERROR:flutter/lib/ui/ui_dart_state.cc(148)] Excepción no controlada: MissingPluginException(No se encontró implementación para el método evaluarJavascript en el canal plugins.flutter.io/webview_0)
E/flutter (17293): #0 MethodChannel.invokeMethod (paquete:flutter/src/services/platform_channel.dart:314:7)
E/aleteo (17293):
E/flutter (17293): #1 MethodChannelWebViewPlatform.evaluateJavascript (paquete:webview_flutter/src/webview_method_channel.dart:90:21)
E/flutter (17293): #2 WebViewController.evaluateJavascript (paquete:webview_flutter/webview_flutter.dart:626:39)
E/flutter (17293): #3 YoutubePlayerController._callMethod (paquete:youtube_player_flutter/src/utils/youtube_player_controller.dart:180:32)
E/flutter (17293): #4 YoutubePlayerController.pause (paquete:youtube_player_flutter/src/utils/youtube_player_controller.dart:194:19)
E/flutter (17293): #5 _VideosScreenState.deactivate (paquete:youvilist/videosScreen.dart:133:34)
E/flutter (17293): #6 StatefulElement.deactivate (paquete:flutter/src/widgets/framework.dart:4135:12)
E/flutter (17293): #7 _InactiveElements._deactivateRecursively (paquete:flutter/src/widgets/framework.dart:1756:13)
E/flutter (17293): #8 SingleChildRenderObjectElement.visitChildren (paquete:flutter/src/widgets/framework.dart:5115:14)
E/flutter (17293): #9 _InactiveElements._deactivateRecursively (paquete:flutter/src/widgets/framework.dart:1758:13)
E/flutter (17293): #10 ComponentElement.visitChildren (paquete:flutter/src/widgets/framework.dart:3990:14)
E/flutter (17293): #11 _InactiveElements._deactivateRecursively (paquete:flutter/src/widgets/framework.dart:1758:13)
E/flutter (17293): #12 SingleChildRenderObjectElement.visitChildren (paquete:flutter/src/widgets/framework.dart:5115:14)
E/flutter (17293): #13 _InactiveElements._deactivateRecursively (paquete:flutter/src/widgets/framework.dart:1758:13)
E/flutter (17293): #14 SingleChildRenderObjectElement.visitChildren (paquete:flutter/src/widgets/framework.dart:5115:14)
E/flutter (17293): #15 _InactiveElements._deactivateRecursively (paquete:flutter/src/widgets/framework.dart:1758:13)
E/flutter (17293): #16 SingleChildRenderObjectElement.visitChildren (paquete:flutter/src/widgets/framework.dart:5115:14)
E/flutter (17293): #17 _InactiveElements._deactivateRecursively (paquete:flutter/src/widgets/framework.dart:1758:13)
E/flutter (17293): #18 SingleChildRenderObjectElement.visitChildren (paquete:flutter/src/widgets/framework.dart:5115:14)
E/flutter (17293): #19 _InactiveElements._deactivateRecursively (paquete:flutter/src/widgets/framework.dart:1758:13)
E/flutter (17293): #20 ComponentElement.visitChildren (paquete:flutter/src/widgets/framework.dart:3990:14)
E/flutter (17293): #21 _InactiveElements._deactivateRecursively (paquete:flutter/src/widgets/framework.dart:1758:13)
E/flutter (17293): #22 ComponentElement.visitChildren (paquete:flutter/src/widgets/framework.dart:3990:14)
E/flutter (17293): #23 _InactiveElements._deactivateRecursively (paquete:flutter/src/widgets/framework.dart:1758:13)
E/flutter (17293): #24 ComponentElement.visitChildren (paquete:flutter/src/widgets/framework.dart:3990:14)
E/flutter (17293): #25 _InactiveElements._deactivateRecursively (paquete:flutter/src/widgets/framework.dart:1758:13)
E/flutter (17293): #26 SingleChildRenderObjectElement.visitChildren (paquete:flutter/src/widgets/framework.dart:5115:14)
E/flutter (17293): #27 _InactiveElements._deactivateRecursively (paquete:flutter/src/widgets/framework.dart:1758:13)
E/flutter (17293): #28 ComponentElement.visitChildren (paquete:flutter/src/widgets/framework.dart:3990:14)
E/flutter (17293): #29 _InactiveElements._deactivateRecursively (paquete:flutter/src/widgets/framework.dart:1758:13)
E/flutter (17293): #30 SingleChildRenderObjectElement.visitChildren (paquete:flutter/src/widgets/framework.dart:5115:14)
E/flutter (17293): #31 _InactiveElements._deactivateRecursively (paquete:flutter/src/widgets/framework.dart:1758:13)
E/flutter (17293): #32 ComponentElement.visitChildren (paquete:flutter/src/widgets/framework.dart:3990:14)
E/flutter (17293): #33 _InactiveElements._deactivateRecursively (paquete:flutter/src/widgets/framework.dart:1758:13)
E/flutter (17293): #34 ComponentElement.visitChildren (paquete:flutter/src/widgets/framework.dart:3990:14)
E/flutter (17293): #35 _InactiveElements._deactivateRecursively (paquete:flutter/src/widgets/framework.dart:1758:13)
E/flutter (17293): #36 SingleChildRenderObjectElement.visitChildren (paquete:flutter/src/widgets/framework.dart:5115:14)
E/flutter (17293): #37 _InactiveElements._deactivateRecursively (paquete:flutter/src/widgets/framework.dart:1758:13)
E/aleteo (17293): #38
Con cromo (17293): [ADVERTENCIA: aw_network_delegate.cc (86)] https://r1---sn-nx5cvox-5uie.googlevideo.com/videoplayback?expire=1574443433&ei=ScXXXdWBL-TyxgKpl6m4Cw&ip=193.140.87.3&id= o-AF9ENbMJOc9OV4_Vekvta7EBAEi0vBUovMb0P1U1ZsBL y itag = 248 y aitags = 133% 2C134% 2C135% 2C136% 2C137% 2C160% 2C242% 2C243% 2C244% 2C247% 2C248% 2C278 y fuente = youtube y requireSSL = yes y mm = 31% 2C29 y Mn = sn-nx5cvox-5uie% 2Csn-nv47lnsy & ms = au% 2Crdu y mv = m y mvi = 0 & pl = 22 y initcwndbps = 652500 & MIME = El video% 2Fwebm y gir = yes y Clen = 167339651 y dur = 1537.920 y lmt = 1570277496757063 y mt = 1574421761 y fvip = 1 & keepalive = yes y fexp = 23842630 & c = WEB_EMBEDDED_PLAYER y TXP = 5535432 & sparams = expirará% 2Cei% 2Cip% 2Cid% 2Caitags% 2Csource% 2Crequiressl% 2Cmime % 2Cgir% 2Cclen% 2Cdur% 2Clmt y sig = ALgxI2wwRgIhAOsRGl_ihaPDxnSFt_2PeeuiQ9wAOw7qpXSrZLniIAn2AiEAgvZLPGOc2uPcqQtKuCuknRk6spcWaQ1Ops0Ff7ucV-y% 3D y lsparams = mm% 2Cmn% 2 cm% 2Cmv% 2Cmvi% 2Cpl% 2Cinitcwndbps y LSIG = AHylml4wRQIgVci2Rv - Q2ngHQ_cosnpEL1lYD13oiqr71DdTHXOYMACIQDYW1uinNm8Mk6Esy8uLh2UObVCy7Eiw8HQGHgbhrtBNg% 3D% 3D y ALR = yes y cpn = PjP8wnSh2Ki85Zot y cver = 20,191 121&range=4746501-6314657&rn=9&rbuf=27201#-3#1
E/chromium(17293): [ERROR:deferred_gpu_command_service.cc(76)] No hay procesador de hardware. Punto muerto probable