Repository: flutter
Issue: [webview_flutter] iOS Flutter got crash because of [FLTWKNavigationDelegate webView:decidePolicyForNavigationAction:decisionHandler:] was not called
Labels: c: crash,platform-ios,engine,p: webview,package,a: production,P2,c: fatal crash,team-ios,triaged-ios

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## Steps to Reproduce

<!-- Please include full steps to reproduce so that we can reproduce the problem. -->

We receive Crashlytics Logs, but we cannot reproduce.


<details>
  <summary>Logs</summary>

Crashlytics Logs
```
Fatal Exception: NSInternalInconsistencyException
0  CoreFoundation                 0x99d78 __exceptionPreprocess
1  libobjc.A.dylib                0x16734 objc_exception_throw
2  CoreFoundation                 0xf1024 __CFDictionaryCreateGeneric
3  WebKit                         0x187180 WebKit::CompletionHandlerCallChecker::~CompletionHandlerCallChecker()
4  WebKit                         0x27cfb8 WTF::Ref<WebKit::CompletionHandlerCallChecker, WTF::RawPtrTraits<WebKit::CompletionHandlerCallChecker> >::~Ref()
5  WebKit                         0x371374 WTF::BlockPtr<void (WKNavigationActionPolicy)> WTF::BlockPtr<void (WKNavigationActionPolicy)>::fromCallable<WebKit::NavigationState::NavigationClient::decidePolicyForNavigationAction(WebKit::WebPageProxy&, WTF::Ref<API::NavigationAction, WTF::RawPtrTraits<API::NavigationAction> >&&, WTF::Ref<WebKit::WebFramePolicyListenerProxy, WTF::RawPtrTraits<WebKit::WebFramePolicyListenerProxy> >&&, API::Object*)::$_15>(WebKit::NavigationState::NavigationClient::decidePolicyForNavigationAction(WebKit::WebPageProxy&, WTF::Ref<API::NavigationAction, WTF::RawPtrTraits<API::NavigationAction> >&&, WTF::Ref<WebKit::WebFramePolicyListenerProxy, WTF::RawPtrTraits<WebKit::WebFramePolicyListenerProxy> >&&, API::Object*)::$_15)::'lambda'(void const*)::__invoke(void const*)
6  libsystem_blocks.dylib         0x1804 _Block_release
7  libsystem_blocks.dylib         0x1804 _Block_release
8  libsystem_blocks.dylib         0x1804 _Block_release
9  libsystem_blocks.dylib         0x1804 _Block_release
10 Flutter                        0x3a208 (シンボルが不足しています UUID d24b4305a5d8348c8a0909c859505f3a)
11 Flutter                        0x3a1a8 (シンボルが不足しています UUID d24b4305a5d8348c8a0909c859505f3a)
12 Flutter                        0x4c86a4 (シンボルが不足しています UUID d24b4305a5d8348c8a0909c859505f3a)
13 Flutter                        0x4c810c (シンボルが不足しています UUID d24b4305a5d8348c8a0909c859505f3a)
14 Flutter                        0x4c7efc (シンボルが不足しています UUID d24b4305a5d8348c8a0909c859505f3a)
15 Flutter                        0x4fd6b0 (シンボルが不足しています UUID d24b4305a5d8348c8a0909c859505f3a)
16 Flutter                        0x508df8 (シンボルが不足しています UUID d24b4305a5d8348c8a0909c859505f3a)
17 Flutter                        0x508850 (シンボルが不足しています UUID d24b4305a5d8348c8a0909c859505f3a)
18 Flutter                        0x3c7294 (シンボルが不足しています UUID d24b4305a5d8348c8a0909c859505f3a)
19 Flutter                        0x3dd070 (シンボルが不足しています UUID d24b4305a5d8348c8a0909c859505f3a)
20 Flutter                        0x3dd854 (シンボルが不足しています UUID d24b4305a5d8348c8a0909c859505f3a)
21 Flutter                        0x2fbbf0 (シンボルが不足しています UUID d24b4305a5d8348c8a0909c859505f3a)
22 Flutter                        0x2ff1bc (シンボルが不足しています UUID d24b4305a5d8348c8a0909c859505f3a)
23 CoreFoundation                 0xaf168 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__
24 CoreFoundation                 0x33144 __CFRunLoopDoTimer
25 CoreFoundation                 0x2d8f0 __CFRunLoopDoTimers
26 CoreFoundation                 0xbfa0 __CFRunLoopRun
27 CoreFoundation                 0x1f6b8 CFRunLoopRunSpecific
28 Flutter                        0x2ff088 (シンボルが不足しています UUID d24b4305a5d8348c8a0909c859505f3a)
29 Flutter                        0x2fe848 (シンボルが不足しています UUID d24b4305a5d8348c8a0909c859505f3a)
30 libsystem_pthread.dylib        0x19ac _pthread_start
31 libsystem_pthread.dylib        0xe68 thread_start
```


Crashlytics Logs
```
Crashed: io.flutter.1.ui
0  FirebaseCrashlytics            0x1f3ac FIRCLSProcessRecordAllThreads + 393 (FIRCLSProcess.c:393)
1  FirebaseCrashlytics            0x1f78c FIRCLSProcessRecordAllThreads + 424 (FIRCLSProcess.c:424)
2  FirebaseCrashlytics            0x166f8 FIRCLSHandler + 34 (FIRCLSHandler.m:34)
3  FirebaseCrashlytics            0x10b94 __FIRCLSExceptionRecord_block_invoke + 215 (FIRCLSException.mm:215)
4  libdispatch.dylib              0x3a2c _dispatch_client_callout + 20
5  libdispatch.dylib              0x12c90 _dispatch_lane_barrier_sync_invoke_and_complete + 56
6  FirebaseCrashlytics            0x10334 FIRCLSExceptionRecord + 219 (FIRCLSException.mm:219)
7  FirebaseCrashlytics            0x1063c FIRCLSExceptionRecordNSException + 109 (FIRCLSException.mm:109)
8  FirebaseCrashlytics            0xff34 FIRCLSTerminateHandler() + 273 (FIRCLSException.mm:273)
9  libc++abi.dylib                0x10f18 std::__terminate(void (*)()) + 20
10 libc++abi.dylib                0x13ebc __cxa_rethrow + 148
11 libobjc.A.dylib                0x186b0 objc_exception_rethrow + 44
12 CoreFoundation                 0x1f7a4 CFRunLoopRunSpecific + 836
13 Flutter                        0x2ff088 (シンボルが不足しています UUID d24b4305a5d8348c8a0909c859505f3a)
14 Flutter                        0x2fe848 (シンボルが不足しています UUID d24b4305a5d8348c8a0909c859505f3a)
15 libsystem_pthread.dylib        0x19ac _pthread_start + 148
16 libsystem_pthread.dylib        0xe68 thread_start + 8
```

<!-- Finally, paste the output of running `flutter doctor -v` here. -->

```
```

</details>


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