title: Flutter How to pass touch event through a platform view to another
body: <p>I have an app with two platform view one of these is a doodle view and another is webview, below is my code</p>
  
  <pre><code>Widget build(BuildContext context) {
      return Scaffold(
        appBar: AppBar(
          title: Text('test'),
        ),
        body: BlocProvider&lt;CourseDocBloc&gt;(
          create: (context) =&gt; CourseDocBloc(),
          child: Container(
            height: double.infinity,
            child: Stack(
              children: &lt;Widget&gt;[
                Listener(
                  child: WebView(
                    initialUrl: 'https://google.com',
                    javascriptMode: JavascriptMode.unrestricted,
                    onPageStarted: (url) {
                      print('start load');
                    },
                    onPageFinished: (url) {
                      print('load finished');
                    },
                  ),
                 onPointerDown: (e) =&gt; {print('web down')},
                 onPointerUp: (e) =&gt; {print('web up')},
                ),
                UiKitView(
                  viewType: 'GLView',
                  hitTestBehavior: PlatformViewHitTestBehavior.transparent, 
                  onPlatformViewCreated: (_) =&gt; created(),
                )
              ],
            ),
          ),
        ),
      );
    }
  </code></pre>
  
  <p>when I set <code>UiKitView</code> <code>hitTestBehavior: PlatformViewHitTestBehavior.transparent</code>，the bottom <code>Listener</code> will print <code>web down, web up ...</code>, but the <code>WebView</code> can not receive touch event, I can't input and click button in html. the <code>GLView</code> is just a OpenGL View to render doodle.</p>
  
  <hr>
  
  <pre><code>flutter doctor
  Doctor summary (to see all details, run flutter doctor -v):
  [✓] Flutter (Channel stable, v1.12.13+hotfix.5, on Mac OS X 10.14.6 18G2022, locale zh-Hans-CN)
  
  [!] Android toolchain - develop for Android devices (Android SDK version 28.0.3)
      ! Some Android licenses not accepted.  To resolve this, run: flutter doctor --android-licenses
  [✓] Xcode - develop for iOS and macOS (Xcode 11.2.1)
  [✓] Android Studio (version 3.5)
  [!] IntelliJ IDEA Ultimate Edition (version 2019.1.2)
      ✗ Flutter plugin not installed; this adds Flutter specific functionality.
      ✗ Dart plugin not installed; this adds Dart specific functionality.
  [✓] VS Code (version 1.40.2)
  [✓] Connected device (1 available)
  
  ! Doctor found issues in 2 categories.
  </code></pre>