Check if reg can run before calling it on Windows (#79905)

packages/flutter_tools/lib/src/web/web_device.dart

@@ -210,6 +210,7 @@ class GoogleChromeDevice extends ChromiumDevice {
     // See https://bugs.chromium.org/p/chromium/issues/detail?id=158372
     String version = 'unknown';
     if (_platform.isWindows) {
+      if (_processManager.canRun('reg')) {
         final ProcessResult result = await _processManager.run(<String>[
           r'reg', 'query', r'HKEY_CURRENT_USER\Software\Google\Chrome\BLBeacon', '/v', 'version',
         ]);
@@ -219,6 +220,7 @@ class GoogleChromeDevice extends ChromiumDevice {
             version = 'Google Chrome ' + parts[parts.length - 2];
           }
         }
+      }
     } else {
       final String chrome = chromeLauncher.findExecutable();
       final ProcessResult result = await _processManager.run(<String>[
@@ -231,7 +233,6 @@ class GoogleChromeDevice extends ChromiumDevice {
     }
     return version.trim();
   }
-
 }
 
 /// The Microsoft Edge browser based on Chromium.
@@ -270,6 +271,7 @@ class MicrosoftEdgeDevice extends ChromiumDevice {
   Future<String> get sdkNameAndVersion async => _sdkNameAndVersion ??= await _getSdkNameAndVersion();
   String _sdkNameAndVersion;
   Future<String> _getSdkNameAndVersion() async {
+    if (_processManager.canRun('reg')) {
       final ProcessResult result = await _processManager.run(<String>[
         r'reg', 'query', r'HKEY_CURRENT_USER\Software\Microsoft\Edge\BLBeacon', '/v', 'version',
       ]);
@@ -279,6 +281,7 @@ class MicrosoftEdgeDevice extends ChromiumDevice {
           return 'Microsoft Edge ' + parts[parts.length - 2];
         }
       }
+    }
     // Return a non-null string so that the tool can validate the version
     // does not meet the constraint above in _meetsVersionConstraint.
     return '';

packages/flutter_tools/test/general.shard/web/devices_test.dart

@@ -255,6 +255,42 @@ void main() {
     expect(processManager, hasNoRemainingExpectations);
   });
 
+  testWithoutContext('Chrome and Edge version check handles missing registry on Windows', () async {
+    final FakeProcessManager processManager = FakeProcessManager.list(<FakeCommand>[]);
+    processManager.excludedExecutables.add('reg');
+
+    final Platform platform = FakePlatform(
+        operatingSystem: 'windows', environment: <String, String>{});
+    final ChromiumLauncher chromeLauncher = ChromiumLauncher(
+      fileSystem: MemoryFileSystem.test(),
+      platform: platform,
+      processManager: processManager,
+      operatingSystemUtils: null,
+      browserFinder: findChromeExecutable,
+      logger: BufferLogger.test(),
+    );
+    final MicrosoftEdgeDevice edgeDevice = MicrosoftEdgeDevice(
+      chromiumLauncher: chromeLauncher,
+      fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
+      processManager: processManager,
+    );
+
+    expect(edgeDevice.isSupported(), true);
+    expect(await edgeDevice.sdkNameAndVersion, '');
+
+    final GoogleChromeDevice chromeDevice = GoogleChromeDevice(
+      chromiumLauncher: chromeLauncher,
+      fileSystem: MemoryFileSystem.test(),
+      logger: BufferLogger.test(),
+      processManager: processManager,
+      platform: platform,
+    );
+
+    expect(chromeDevice.isSupported(), true);
+    expect(await chromeDevice.sdkNameAndVersion, 'unknown');
+  });
+
   testWithoutContext('Edge is not supported on versions less than 73', () async {
     final FakeProcessManager processManager = FakeProcessManager.list(<FakeCommand>[
       const FakeCommand(