[webview] Add macOS support in implementation package (#6221)

Adds initial support for macOS.

Known limitations:
- Scroll APIs are not supported, and currently throw unimplemented. Longer term we could consider JS polyfills, but we'd probably want to make them opt-in since injecting JS into every page has some risks.
- Setting the background color doesn't work since the view structure is different on macOS. We may be able to use a layer-backed view to support this in the future.

Since many use cases don't require these features, my preference is to land this without that support, rather than blocking on having full parity, and then the specific features can be added later based on community interest (demand and/or contributions).

This requires 3.24, as 3.22 does not yet have gesture support for macOS platform views, and pushing this to users without gesture support would be very confusing.

Part of flutter/flutter#41725

Author: stuartmorgan-g

packages/webview_flutter/webview_flutter_wkwebview/CHANGELOG.md

@@ -1,6 +1,6 @@
-## NEXT
+## 3.15.0
 
-* Updates minimum supported SDK version to Flutter 3.19/Dart 3.3.
+* Adds macOS support.
 
 ## 3.14.0
 
@@ -92,7 +92,7 @@
 
 * Introduces `NSError.toString` for better diagnostics.
 
-## 3.6.2 
+## 3.6.2
 
 * Fixes unawaited_futures violations.
 

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFDataConvertersTests.m renamed to packages/webview_flutter/webview_flutter_wkwebview/darwin/Tests/FWFDataConvertersTests.m

@@ -2,10 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-@import Flutter;
 @import XCTest;
 @import webview_flutter_wkwebview;
 
+#if TARGET_OS_OSX
+@import FlutterMacOS;
+#else
+@import Flutter;
+#endif
+
 #import <OCMock/OCMock.h>
 
 @interface FWFDataConvertersTests : XCTestCase
@@ -61,8 +66,8 @@ - (void)testFWFWKNavigationActionDataFromNavigationAction {
 
   OCMStub([mockNavigationAction navigationType]).andReturn(WKNavigationTypeReload);
 
-  NSURLRequest *request =
-      [NSURLRequest requestWithURL:[NSURL URLWithString:@"https://www.flutter.dev/"]];
+  NSURL *testURL = [NSURL URLWithString:@"https://www.flutter.dev/"];
+  NSURLRequest *request = [NSURLRequest requestWithURL:testURL];
   OCMStub([mockNavigationAction request]).andReturn(request);
 
   WKFrameInfo *mockFrameInfo = OCMClassMock([WKFrameInfo class]);
@@ -76,8 +81,8 @@ - (void)testFWFWKNavigationActionDataFromNavigationAction {
 }
 
 - (void)testFWFNSUrlRequestDataFromNSURLRequest {
-  NSMutableURLRequest *request =
-      [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"https://www.flutter.dev/"]];
+  NSURL *testURL = [NSURL URLWithString:@"https://www.flutter.dev/"];
+  NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:testURL];
   request.HTTPMethod = @"POST";
   request.HTTPBody = [@"aString" dataUsingEncoding:NSUTF8StringEncoding];
   request.allHTTPHeaderFields = @{@"a" : @"field"};
@@ -137,7 +142,7 @@ - (void)testFWFWKSecurityOriginDataFromWKSecurityOrigin {
   XCTAssertEqualObjects(data.protocol, @"protocol");
 }
 
-- (void)testFWFWKPermissionDecisionFromData API_AVAILABLE(ios(15.0)) {
+- (void)testFWFWKPermissionDecisionFromData API_AVAILABLE(ios(15.0), macos(12)) {
   XCTAssertEqual(FWFNativeWKPermissionDecisionFromData(
                      [FWFWKPermissionDecisionData makeWithValue:FWFWKPermissionDecisionDeny]),
                  WKPermissionDecisionDeny);
@@ -149,7 +154,7 @@ - (void)testFWFWKPermissionDecisionFromData API_AVAILABLE(ios(15.0)) {
                  WKPermissionDecisionPrompt);
 }
 
-- (void)testFWFWKMediaCaptureTypeDataFromWKMediaCaptureType API_AVAILABLE(ios(15.0)) {
+- (void)testFWFWKMediaCaptureTypeDataFromWKMediaCaptureType API_AVAILABLE(ios(15.0), macos(12)) {
   XCTAssertEqual(
       FWFWKMediaCaptureTypeDataFromNativeWKMediaCaptureType(WKMediaCaptureTypeCamera).value,
       FWFWKMediaCaptureTypeCamera);

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFErrorTests.m renamed to packages/webview_flutter/webview_flutter_wkwebview/darwin/Tests/FWFErrorTests.m

@@ -2,10 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-@import Flutter;
 @import XCTest;
 @import webview_flutter_wkwebview;
 
+#if TARGET_OS_OSX
+@import FlutterMacOS;
+#else
+@import Flutter;
+#endif
+
 #import <OCMock/OCMock.h>
 
 @interface FWFHTTPCookieStoreHostApiTests : XCTestCase
@@ -47,9 +52,8 @@ - (void)testSetCookie {
                                 completion:^(FlutterError *error) {
                                   blockError = error;
                                 }];
-  OCMVerify([mockHttpCookieStore
-              setCookie:[NSHTTPCookie cookieWithProperties:@{NSHTTPCookieName : @"hello"}]
-      completionHandler:OCMOCK_ANY]);
+  NSHTTPCookie *cookie = [NSHTTPCookie cookieWithProperties:@{NSHTTPCookieName : @"hello"}];
+  OCMVerify([mockHttpCookieStore setCookie:cookie completionHandler:OCMOCK_ANY]);
   XCTAssertNil(blockError);
 }
 @end

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFHTTPCookieStoreHostApiTests.m renamed to packages/webview_flutter/webview_flutter_wkwebview/darwin/Tests/FWFHTTPCookieStoreHostApiTests.m

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#import <XCTest/XCTest.h>
+@import XCTest;
 
 @import webview_flutter_wkwebview;
 #if __has_include(<webview_flutter_wkwebview/webview-umbrella.h>)

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFInstanceManagerTests.m renamed to packages/webview_flutter/webview_flutter_wkwebview/darwin/Tests/FWFInstanceManagerTests.m

@@ -2,10 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-@import Flutter;
 @import XCTest;
 @import webview_flutter_wkwebview;
 
+#if TARGET_OS_OSX
+@import FlutterMacOS;
+#else
+@import Flutter;
+#endif
+
 #import <OCMock/OCMock.h>
 
 @interface FWFNavigationDelegateHostApiTests : XCTestCase
@@ -117,8 +122,8 @@ - (void)testDecidePolicyForNavigationAction {
   [instanceManager addDartCreatedInstance:mockWebView withIdentifier:1];
 
   WKNavigationAction *mockNavigationAction = OCMClassMock([WKNavigationAction class]);
-  OCMStub([mockNavigationAction request])
-      .andReturn([NSURLRequest requestWithURL:[NSURL URLWithString:@"https://www.flutter.dev"]]);
+  NSURL *testURL = [NSURL URLWithString:@"https://www.flutter.dev"];
+  OCMStub([mockNavigationAction request]).andReturn([NSURLRequest requestWithURL:testURL]);
 
   WKFrameInfo *mockFrameInfo = OCMClassMock([WKFrameInfo class]);
   OCMStub([mockFrameInfo isMainFrame]).andReturn(YES);
@@ -258,10 +263,10 @@ - (void)testDidReceiveAuthenticationChallenge {
   NSURLCredential *__block callbackCredential;
   [mockDelegate webView:mockWebView
       didReceiveAuthenticationChallenge:mockChallenge
-                      completionHandler:^(NSURLSessionAuthChallengeDisposition disposition,
-                                          NSURLCredential *credential) {
-                        callbackDisposition = disposition;
-                        callbackCredential = credential;
+                      completionHandler:^(NSURLSessionAuthChallengeDisposition dispositionArg,
+                                          NSURLCredential *credentialArg) {
+                        callbackDisposition = dispositionArg;
+                        callbackCredential = credentialArg;
                       }];
 
   XCTAssertEqual(callbackDisposition, NSURLSessionAuthChallengeCancelAuthenticationChallenge);

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFNavigationDelegateHostApiTests.m renamed to packages/webview_flutter/webview_flutter_wkwebview/darwin/Tests/FWFNavigationDelegateHostApiTests.m

@@ -2,10 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-@import Flutter;
 @import XCTest;
 @import webview_flutter_wkwebview;
 
+#if TARGET_OS_OSX
+@import FlutterMacOS;
+#else
+@import Flutter;
+#endif
+
 #import <OCMock/OCMock.h>
 
 @interface FWFObjectHostApiTests : XCTestCase
@@ -139,8 +144,10 @@ - (void)testObserveValueForKeyPath {
                                  return value[0].value == FWFNSKeyValueChangeKeyEnumOldValue;
                                }]
                              changeValues:[OCMArg checkWithBlock:^BOOL(id value) {
-                               FWFObjectOrIdentifier *object = (FWFObjectOrIdentifier *)value[0];
-                               return !object.isIdentifier && [@"key" isEqual:object.value];
+                               FWFObjectOrIdentifier *changeObject =
+                                   (FWFObjectOrIdentifier *)value[0];
+                               return !changeObject.isIdentifier &&
+                                      [@"key" isEqual:changeObject.value];
                              }]
                                completion:OCMOCK_ANY]);
 }
@@ -173,8 +180,10 @@ - (void)testObserveValueForKeyPathWithIdentifier {
                                  return value[0].value == FWFNSKeyValueChangeKeyEnumOldValue;
                                }]
                              changeValues:[OCMArg checkWithBlock:^BOOL(id value) {
-                               FWFObjectOrIdentifier *object = (FWFObjectOrIdentifier *)value[0];
-                               return object.isIdentifier && [@(2) isEqual:object.value];
+                               FWFObjectOrIdentifier *changeObject =
+                                   (FWFObjectOrIdentifier *)value[0];
+                               return changeObject.isIdentifier &&
+                                      [@(2) isEqual:changeObject.value];
                              }]
                                completion:OCMOCK_ANY]);
 }

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFObjectHostApiTests.m renamed to packages/webview_flutter/webview_flutter_wkwebview/darwin/Tests/FWFObjectHostApiTests.m

@@ -2,10 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-@import Flutter;
 @import XCTest;
 @import webview_flutter_wkwebview;
 
+#if TARGET_OS_OSX
+@import FlutterMacOS;
+#else
+@import Flutter;
+#endif
+
 #import <OCMock/OCMock.h>
 
 @interface FWFPreferencesHostApiTests : XCTestCase

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFPreferencesHostApiTests.m renamed to packages/webview_flutter/webview_flutter_wkwebview/darwin/Tests/FWFPreferencesHostApiTests.m

@@ -2,10 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-@import Flutter;
 @import XCTest;
 @import webview_flutter_wkwebview;
 
+#if TARGET_OS_OSX
+@import FlutterMacOS;
+#else
+@import Flutter;
+#endif
+
 #import <OCMock/OCMock.h>
 
 @interface FWFScriptMessageHandlerHostApiTests : XCTestCase

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFScriptMessageHandlerHostApiTests.m renamed to packages/webview_flutter/webview_flutter_wkwebview/darwin/Tests/FWFScriptMessageHandlerHostApiTests.m

@@ -2,6 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include "TargetConditionals.h"
+
+// The scroll view delegate does not exist on macOS.
+#if !TARGET_OS_OSX
+
 @import Flutter;
 @import XCTest;
 @import webview_flutter_wkwebview;
@@ -80,3 +85,5 @@ - (void)testOnScrollViewDidScrollForDelegateWithIdentifier {
                                                    completion:OCMOCK_ANY]);
 }
 @end
+
+#endif  // !TARGET_OS_OSX

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFScrollViewDelegateHostApiTests.m renamed to packages/webview_flutter/webview_flutter_wkwebview/darwin/Tests/FWFScrollViewDelegateHostApiTests.m

@@ -2,6 +2,11 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#import "TargetConditionals.h"
+
+// Scroll view APIs do not existing on macOS.
+#if !TARGET_OS_OSX
+
 @import Flutter;
 @import XCTest;
 @import webview_flutter_wkwebview;
@@ -79,3 +84,5 @@ - (void)testSetDelegateForScrollView {
   XCTAssertNil(error);
 }
 @end
+
+#endif  // !TARGET_OS_OSX

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFScrollViewHostApiTests.m renamed to packages/webview_flutter/webview_flutter_wkwebview/darwin/Tests/FWFScrollViewHostApiTests.m

@@ -2,13 +2,18 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-@import Flutter;
 @import XCTest;
 @import webview_flutter_wkwebview;
 #if __has_include(<webview_flutter_wkwebview/webview-umbrella.h>)
 @import webview_flutter_wkwebview.Test;
 #endif
 
+#if TARGET_OS_OSX
+@import FlutterMacOS;
+#else
+@import Flutter;
+#endif
+
 #import <OCMock/OCMock.h>
 
 @interface FWFUIDelegateHostApiTests : XCTestCase
@@ -77,8 +82,8 @@ - (void)testOnCreateWebViewForDelegateWithIdentifier {
       .ignoringNonObjectArgs();
 
   WKNavigationAction *mockNavigationAction = OCMClassMock([WKNavigationAction class]);
-  OCMStub([mockNavigationAction request])
-      .andReturn([NSURLRequest requestWithURL:[NSURL URLWithString:@"https://www.flutter.dev"]]);
+  NSURL *testURL = [NSURL URLWithString:@"https://www.flutter.dev"];
+  OCMStub([mockNavigationAction request]).andReturn([NSURLRequest requestWithURL:testURL]);
 
   WKFrameInfo *mockFrameInfo = OCMClassMock([WKFrameInfo class]);
   OCMStub([mockFrameInfo isMainFrame]).andReturn(YES);
@@ -100,7 +105,7 @@ - (void)testOnCreateWebViewForDelegateWithIdentifier {
                                     completion:OCMOCK_ANY]);
 }
 
-- (void)testRequestMediaCapturePermissionForOrigin API_AVAILABLE(ios(15.0)) {
+- (void)testRequestMediaCapturePermissionForOrigin API_AVAILABLE(ios(15.0), macos(12)) {
   FWFInstanceManager *instanceManager = [[FWFInstanceManager alloc] init];
 
   FWFUIDelegate *mockDelegate = [self mockDelegateWithManager:instanceManager identifier:0];

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFUIDelegateHostApiTests.m renamed to packages/webview_flutter/webview_flutter_wkwebview/darwin/Tests/FWFUIDelegateHostApiTests.m

@@ -2,6 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#import "TargetConditionals.h"
+
+#if !TARGET_OS_OSX
+
 @import Flutter;
 @import XCTest;
 @import webview_flutter_wkwebview;
@@ -47,3 +51,5 @@ - (void)testSetOpaque {
 }
 
 @end
+
+#endif  // !TARGET_OS_OSX

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFUIViewHostApiTests.m renamed to packages/webview_flutter/webview_flutter_wkwebview/darwin/Tests/FWFUIViewHostApiTests.m

@@ -2,10 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-@import Flutter;
 @import XCTest;
 @import webview_flutter_wkwebview;
 
+#if TARGET_OS_OSX
+@import FlutterMacOS;
+#else
+@import Flutter;
+#endif
+
 #import <OCMock/OCMock.h>
 
 @interface FWFURLAuthenticationChallengeHostApiTests : XCTestCase

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFURLAuthenticationChallengeHostApiTests.m renamed to packages/webview_flutter/webview_flutter_wkwebview/darwin/Tests/FWFURLAuthenticationChallengeHostApiTests.m

@@ -2,10 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-@import Flutter;
 @import XCTest;
 @import webview_flutter_wkwebview;
 
+#if TARGET_OS_OSX
+@import FlutterMacOS;
+#else
+@import Flutter;
+#endif
+
 #import <OCMock/OCMock.h>
 
 @interface FWFURLCredentialHostApiTests : XCTestCase

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFURLCredentialHostApiTests.m renamed to packages/webview_flutter/webview_flutter_wkwebview/darwin/Tests/FWFURLCredentialHostApiTests.m

@@ -2,10 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-@import Flutter;
 @import XCTest;
 @import webview_flutter_wkwebview;
 
+#if TARGET_OS_OSX
+@import FlutterMacOS;
+#else
+@import Flutter;
+#endif
+
 #import <OCMock/OCMock.h>
 
 @interface FWFURLProtectionSpaceHostApiTests : XCTestCase

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFURLProtectionSpaceHostApiTests.m renamed to packages/webview_flutter/webview_flutter_wkwebview/darwin/Tests/FWFURLProtectionSpaceHostApiTests.m

@@ -2,10 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-@import Flutter;
 @import XCTest;
 @import webview_flutter_wkwebview;
 
+#if TARGET_OS_OSX
+@import FlutterMacOS;
+#else
+@import Flutter;
+#endif
+
 #import <OCMock/OCMock.h>
 
 @interface FWFURLTests : XCTestCase