Fix Network tab not capturing requests after hot restart and clear

[muhammadkamel]

Summary

• Re-enable HTTP timeline logging and socket profiling on new isolates by listening to IsolateManager.onIsolateCreated, fixing the Network tab freeze after hot restart (#9783, #9839).
• Reset HTTP and socket refresh timestamps using the VM timeline when Clear is pressed, so new requests continue to appear after clearing while recording.
• Keep the Network tab search field enabled while recording or when requests are visible, including after Clear and while paused (#9853).
• Expose IsolateManager.onIsolateCreated in devtools_app_shared for isolate lifecycle detection.
• Add unit and widget tests covering hot restart, clear, and combined lifecycle scenarios.

Test plan

• flutter test test/screens/network/network_hot_restart_test.dart
• flutter test test/screens/network/network_clear_test.dart
• flutter test test/screens/network/network_profiler_test.dart
• ./tool/bin/dt presubmit --fix
• Manually verified on Android emulator (Flutter App Project): reproduced with SDK DevTools, fixed with locally built DevTools from this branch

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[gemini-code-assist]

Code Review

This pull request addresses issues in the Network profiler where capturing stopped after a hot restart or after clearing recorded data, and introduces an onIsolateCreated stream to detect new isolates. The review feedback highlights a regression where the search field is disabled when recording is paused (even if requests exist), and suggests wrapping asynchronous VM service calls in error-handling blocks to prevent unhandled RPCErrors.

[gemini-code-assist]

[MUST-FIX] Disabling the search field when _recording is false will prevent users from searching through captured requests when recording is paused. To fix this regression while still keeping the search field enabled when the list is cleared during active recording, the search field should be enabled if recording is active OR if there are existing requests in the list.

Suggested change

	searchFieldEnabled: _recording,
	searchFieldEnabled: _recording || controller.filteredData.value.isNotEmpty,

References

1. Categorize Severity: Prefix every comment with a severity: [MUST-FIX] for logical bugs. ^(link)

[gemini-code-assist]

[CONCERN] Wrap the call to _enableNetworkTrafficRecordingOnAllIsolates() in allowedError to safely handle any potential RPCErrors that might occur if the newly created isolate is quickly destroyed or if the connection is lost during the asynchronous operation.

Suggested change

	await _enableNetworkTrafficRecordingOnAllIsolates();
	await allowedError(_enableNetworkTrafficRecordingOnAllIsolates());

References

1. Categorize Severity: Prefix every comment with a severity: [CONCERN] for robustness/maintainability issues. ^(link)

[gemini-code-assist]

[CONCERN] Wrap the VM service calls in clearData() in a try-catch block for RPCError to prevent unhandled exceptions (and potential UI crashes) if the connection is lost or the service is disposed while clearing data.

  Future<void> clearData() async {
    final service = serviceConnection.serviceManager.service;
    if (service == null) return;

    try {
      final timestamp = (await service.getVMTimelineMicros()).timestamp!;
      networkController.lastSocketDataRefreshMicros = timestamp;
      await service.forEachIsolate((isolate) async {
        lastHttpDataRefreshTimePerIsolate[isolate.id!] = timestamp;
      });
      await _clearSocketProfile();
      await _clearHttpProfile();
    } on RPCError catch (e) {
      if (!e.isServiceDisposedError) {
        rethrow;
      }
    }
  }

References

1. Categorize Severity: Prefix every comment with a severity: [CONCERN] for robustness/maintainability issues. ^(link)