don't warn on CHROME_EXECUTABLE missing if we've already located it. (#34079)

packages/flutter_tools/lib/src/doctor.dart

@@ -463,6 +463,19 @@ class ValidationMessage {
 
   @override
   String toString() => message;
+
+  @override
+  bool operator ==(Object other) {
+    if (other.runtimeType != runtimeType) {
+      return false;
+    }
+    final ValidationMessage typedOther = other;
+    return typedOther.message == message
+      && typedOther.type == type;
+  }
+
+  @override
+  int get hashCode => type.hashCode ^ message.hashCode;
 }
 
 class FlutterValidator extends DoctorValidator {

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

@@ -71,7 +71,7 @@ class WebDevice extends Device {
   Future<bool> get isLocalEmulator async => false;
 
   @override
-  bool isSupported() => flutterWebEnabled;
+  bool isSupported() => flutterWebEnabled && canFindChrome();
 
   @override
   String get name => 'web';
@@ -81,6 +81,9 @@ class WebDevice extends Device {
 
   @override
   Future<String> get sdkNameAndVersion async {
+    if (!isSupported()) {
+      return 'unknown';
+    }
     // See https://bugs.chromium.org/p/chromium/issues/detail?id=158372
     String version = 'unknown';
     if (platform.isWindows) {

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

@@ -17,10 +17,17 @@ class WebValidator extends DoctorValidator {
     final bool canRunChrome = canFindChrome();
     final List<ValidationMessage> messages = <ValidationMessage>[];
     if (platform.environment.containsKey(kChromeEnvironment)) {
+      if (!canRunChrome) {
+        messages.add(ValidationMessage.hint('$chrome is not executable.'));
+      } else {
         messages.add(ValidationMessage('$kChromeEnvironment = $chrome'));
+      }
     } else {
-      messages.add(ValidationMessage('Chrome at $chrome'));
+      if (!canRunChrome) {
         messages.add(ValidationMessage.hint('$kChromeEnvironment not set'));
+      } else {
+        messages.add(ValidationMessage('Chrome at $chrome'));
+      }
     }
     if (!canRunChrome) {
       return ValidationResult(

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

@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 import '../base/context.dart';
-import '../base/file_system.dart';
 import '../base/platform.dart';
 import '../base/process_manager.dart';
 import '../doctor.dart';
@@ -40,12 +39,9 @@ class WebWorkflow extends Workflow {
 /// Whether we can locate the chrome executable.
 bool canFindChrome() {
   final String chrome = findChromeExecutable();
-  if (platform.isLinux) {
+  try {
     return processManager.canRun(chrome);
-  } else if (platform.isMacOS) {
-    return fs.file(chrome).existsSync();
-  } else if (platform.isWindows) {
-    return fs.file(chrome).existsSync();
-  }
+  } on ArgumentError {
     return false;
+  }
 }

packages/flutter_tools/test/web/devices_test.dart

@@ -28,14 +28,13 @@ void main() {
     });
     testUsingContext('Invokes version command on non-Windows platforms', () async{
       when(mockPlatform.isWindows).thenReturn(false);
-      when(mockPlatform.environment).thenReturn(<String, String>{
-        kChromeEnvironment: 'chrome.foo'
-      });
+      when(mockProcessManager.canRun('chrome.foo')).thenReturn(true);
       when(mockProcessManager.run(<String>['chrome.foo', '--version'])).thenAnswer((Invocation invocation) async {
         return MockProcessResult(0, 'ABC');
       });
       final WebDevice webDevice = WebDevice();
 
+      expect(webDevice.isSupported(), true);
       expect(await webDevice.sdkNameAndVersion, 'ABC');
     }, overrides: <Type, Generator>{
       Platform: () => mockPlatform,
@@ -44,6 +43,7 @@ void main() {
 
     testUsingContext('Invokes different version command on windows.', () async {
       when(mockPlatform.isWindows).thenReturn(true);
+      when(mockProcessManager.canRun('chrome.foo')).thenReturn(true);
       when(mockProcessManager.run(<String>[
         'reg',
         'query',
@@ -55,6 +55,7 @@ void main() {
       });
       final WebDevice webDevice = WebDevice();
 
+      expect(webDevice.isSupported(), true);
       expect(await webDevice.sdkNameAndVersion, 'Google Chrome 74.0.0');
     }, overrides: <Type, Generator>{
       Platform: () => mockPlatform,
@@ -64,7 +65,10 @@ void main() {
 }
 
 class MockChromeLauncher extends Mock implements ChromeLauncher {}
-class MockPlatform extends Mock implements Platform {}
+class MockPlatform extends Mock implements Platform {
+  @override
+  Map<String, String> environment = <String, String>{'FLUTTER_WEB': 'true', kChromeEnvironment: 'chrome.foo'};
+}
 class MockProcessManager extends Mock implements ProcessManager {}
 class MockProcessResult extends Mock implements ProcessResult {
   MockProcessResult(this.exitCode, this.stdout);

packages/flutter_tools/test/web/web_validator_test.dart

@@ -2,12 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-import 'package:flutter_tools/src/base/file_system.dart';
 import 'package:flutter_tools/src/base/platform.dart';
 import 'package:flutter_tools/src/doctor.dart';
 import 'package:flutter_tools/src/web/chrome.dart';
 import 'package:flutter_tools/src/web/web_validator.dart';
 import 'package:mockito/mockito.dart';
+import 'package:process/process.dart';
 
 import '../src/common.dart';
 import '../src/testbed.dart';
@@ -17,14 +17,16 @@ void main() {
     Testbed testbed;
     WebValidator webValidator;
     MockPlatform mockPlatform;
+    MockProcessManager mockProcessManager;
 
     setUp(() {
+      mockProcessManager = MockProcessManager();
       testbed = Testbed(setup: () {
-        fs.file(kMacOSExecutable).createSync(recursive: true);
-        fs.file('chrome_foo').createSync();
+        when(mockProcessManager.canRun(kMacOSExecutable)).thenReturn(true);
         return null;
       }, overrides: <Type, Generator>{
         Platform: () => mockPlatform,
+        ProcessManager: () => mockProcessManager,
       });
       webValidator = const WebValidator();
       mockPlatform = MockPlatform();
@@ -39,10 +41,19 @@ void main() {
     }));
 
     test('Can notice missing macOS executable ', () => testbed.run(() async {
-      fs.file(kMacOSExecutable).deleteSync();
+      when(mockProcessManager.canRun(kMacOSExecutable)).thenReturn(false);
       final ValidationResult result = await webValidator.validate();
       expect(result.type, ValidationType.missing);
     }));
+
+    test('Doesn\'t warn about CHROME_EXECUTABLE unless it cant find chrome ', () => testbed.run(() async {
+      when(mockProcessManager.canRun(kMacOSExecutable)).thenReturn(false);
+      final ValidationResult result = await webValidator.validate();
+      expect(result.messages, <ValidationMessage>[
+        ValidationMessage.hint('CHROME_EXECUTABLE not set')
+      ]);
+      expect(result.type, ValidationType.missing);
+    }));
   });
 }
 
@@ -50,3 +61,5 @@ class MockPlatform extends Mock implements Platform  {
   @override
   Map<String, String> get environment => const <String, String>{};
 }
+
+class MockProcessManager extends Mock implements ProcessManager {}
\ No newline at end of file

packages/flutter_tools/test/web/workflow_test.dart

@@ -83,6 +83,7 @@ void main() {
     }));
 
     test('does not apply on other platforms', () => testbed.run(() {
+      when(mockProcessManager.canRun('chrome')).thenReturn(false);
       expect(workflow.appliesToHostPlatform, false);
       expect(workflow.canLaunchDevices, false);
       expect(workflow.canListDevices, false);