[iOS] Standardize handlers for settings view controllers.

Handler setup for settings view controllers was inconsistent. Most have
access to a 'dispatcher' property that combines Application, Browser,
and BrowsingData commands. This property is defined in the
SettingsRootViewControlling property that most of these view controllers
conform to by virtue of being subclasses of SettingsRootTableView-Controller.

Others also have a separate property for Snackbar commands, and some
have an additional Application commands handler, even though that can
be done through the Dispatcher.

Command injection was also heterogenous; the dispatcher property was
typically set in the various convenience initializers of Settings
NavigationController via various methods of the delegate protocol, even
though all of these initializers also pass a Browser which provides
a command dispatcher that can be used for all of these handlers.

SettingsNavigationControllerDelegate defined three methods for fetching
command handlers. One got the three-command 'handler for settings', one
got just an Application command handler, and one got the Snackbar
handler. Some implementations of this protocol had one or more of these
methods as no-ops with NOTREACHED(); this is not something that should
ever be done in a protocol (where parts of the API can just be makred
@optional if they are actually optional).

This CL standardizes things by:

- Defining separate handler properties for all command protocols in
SettingsRootViewControlling.

- Getting rid of the mis-named 'dispatcher' property.

- Setting handlers on view controllers based on the Browser that
SettingsNavigationController is initialized with, and removing the
handler fetching methods from that class's delegate protocol.

- Ensuring all handlers are set for all view controllers. Some utility
functions/methods are added to make this less boilerplate-y, although
coordinators do use the same chunk of setup code to set all of the
handlers on their view controllers.

Tests are updated to configure command dispatch correctly.

After this CL lands, follow-up CLs will prune some of these command
protocols from SettingsRootViewControlling, to remove unneeded
dependencies.

Bug: 1045047
Change-Id: I4bdcda997763170595e2416df39575cc7b9e33cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4895672
Reviewed-by: Gauthier Ambard <gambard@chromium.org>
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Commit-Queue: Mark Cogan <marq@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1210137}

ios/chrome/browser/shared/coordinator/scene/scene_controller.mm

@@ -1658,8 +1658,7 @@ - (void)presentReportAnIssueViewController:(UIViewController*)baseViewController
     self.settingsNavigationController =
         [SettingsNavigationController userFeedbackControllerForBrowser:browser
                                                               delegate:self
-                                                      userFeedbackData:data
-                                                               handler:handler];
+                                                      userFeedbackData:data];
     [baseViewController presentViewController:self.settingsNavigationController
                                      animated:YES
                                    completion:nil];
@@ -2395,24 +2394,6 @@ - (void)settingsWasDismissed {
   self.settingsNavigationController = nil;
 }
 
-- (id<ApplicationCommands, BrowserCommands>)handlerForSettings {
-  // Assume that settings always wants the dispatcher from the main BVC.
-  return static_cast<id<ApplicationCommands, BrowserCommands>>(
-      self.mainInterface.browser->GetCommandDispatcher());
-}
-
-- (id<ApplicationCommands>)handlerForApplicationCommands {
-  // Assume that settings always wants the dispatcher from the main BVC.
-  return HandlerForProtocol(self.mainInterface.browser->GetCommandDispatcher(),
-                            ApplicationCommands);
-}
-
-- (id<SnackbarCommands>)handlerForSnackbarCommands {
-  // Assume that settings always wants the dispatcher from the main BVC.
-  return HandlerForProtocol(self.mainInterface.browser->GetCommandDispatcher(),
-                            SnackbarCommands);
-}
-
 #pragma mark - TabGridCoordinatorDelegate
 
 - (void)tabGrid:(TabGridCoordinator*)tabGrid

ios/chrome/browser/ui/authentication/BUILD.gn

@@ -160,6 +160,7 @@ source_set("unit_tests") {
     "//ios/chrome/browser/ui/authentication/unified_consent:unified_consent_ui",
     "//ios/chrome/browser/unified_consent/model",
     "//ios/chrome/test:test_support",
+    "//ios/testing:protocol_fake",
     "//ios/web/public/test",
     "//testing/gtest",
     "//third_party/ocmock",

ios/chrome/browser/ui/authentication/authentication_flow_performer.mm

@@ -599,22 +599,6 @@ - (void)settingsWasDismissed {
   _navigationController = nil;
 }
 
-- (id<ApplicationCommands, BrowserCommands, BrowsingDataCommands>)
-    handlerForSettings {
-  NOTREACHED();
-  return nil;
-}
-
-- (id<ApplicationCommands>)handlerForApplicationCommands {
-  NOTREACHED();
-  return nil;
-}
-
-- (id<SnackbarCommands>)handlerForSnackbarCommands {
-  NOTREACHED();
-  return nil;
-}
-
 #pragma mark - Private
 
 - (void)updateUserPolicyNotificationStatusIfNeeded:(PrefService*)prefService {

ios/chrome/browser/ui/authentication/authentication_flow_performer_unittest.mm

@@ -4,15 +4,23 @@
 
 #import "ios/chrome/browser/ui/authentication/authentication_flow_performer.h"
 
+#import <objc/runtime.h>
+
 #import "ios/chrome/browser/shared/model/application_context/application_context.h"
 #import "ios/chrome/browser/shared/model/browser/test/test_browser.h"
 #import "ios/chrome/browser/shared/model/browser_state/test_chrome_browser_state.h"
+#import "ios/chrome/browser/shared/public/commands/application_commands.h"
+#import "ios/chrome/browser/shared/public/commands/browser_commands.h"
+#import "ios/chrome/browser/shared/public/commands/browsing_data_commands.h"
+#import "ios/chrome/browser/shared/public/commands/command_dispatcher.h"
+#import "ios/chrome/browser/shared/public/commands/snackbar_commands.h"
 #import "ios/chrome/browser/signin/authentication_service.h"
 #import "ios/chrome/browser/signin/authentication_service_factory.h"
 #import "ios/chrome/browser/signin/fake_authentication_service_delegate.h"
 #import "ios/chrome/browser/signin/fake_system_identity.h"
 #import "ios/chrome/browser/signin/fake_system_identity_manager.h"
 #import "ios/chrome/test/ios_chrome_scoped_testing_local_state.h"
+#import "ios/testing/protocol_fake.h"
 #import "ios/web/public/test/web_task_environment.h"
 #import "testing/platform_test.h"
 #import "third_party/ocmock/gtest_support.h"
@@ -35,6 +43,20 @@ void SetUp() override {
         std::make_unique<FakeAuthenticationServiceDelegate>());
     browser_ = std::make_unique<TestBrowser>(browser_state_.get());
     fake_identity_ = [FakeSystemIdentity fakeIdentity1];
+
+    NSArray<Protocol*>* command_protocols = @[
+      @protocol(ApplicationCommands), @protocol(BrowserCommands),
+      @protocol(BrowsingDataCommands), @protocol(ApplicationSettingsCommands),
+      @protocol(SnackbarCommands)
+    ];
+    fake_command_endpoint_ =
+        [[ProtocolFake alloc] initWithProtocols:command_protocols];
+    for (Protocol* protocol in command_protocols) {
+      [browser_->GetCommandDispatcher()
+          startDispatchingToTarget:fake_command_endpoint_
+                       forProtocol:protocol];
+    }
+
     FakeSystemIdentityManager* fake_system_identity_manager =
         FakeSystemIdentityManager::FromSystemIdentityManager(
             GetApplicationContext()->GetSystemIdentityManager());
@@ -59,6 +81,7 @@ void TearDown() override {
   id<AuthenticationFlowPerformerDelegate>
       authentication_flow_performer_delegate_mock_ = nil;
   FakeSystemIdentity* fake_identity_ = nil;
+  ProtocolFake* fake_command_endpoint_ = nil;
 };
 
 // Tests interrupt call with `SigninCoordinatorInterrupt::UIShutdownNoDismiss`.

ios/chrome/browser/ui/settings/BUILD.gn

@@ -365,6 +365,7 @@ source_set("unit_tests") {
     "//ios/chrome/common",
     "//ios/chrome/test:test_support",
     "//ios/chrome/test/app:test_support",
+    "//ios/testing:protocol_fake",
     "//ios/web/public/test",
     "//net",
     "//net:test_support",

ios/chrome/browser/ui/settings/about_chrome_table_view_controller.h

@@ -16,12 +16,6 @@
 @interface AboutChromeTableViewController
     : SettingsRootTableViewController <SettingsControllerProtocol>
 
-// ApplicationCommands handler.
-@property(nonatomic, weak) id<ApplicationCommands> applicationCommandsHandler;
-
-// SnackbarCommands handler.
-@property(nonatomic, weak) id<SnackbarCommands> snackbarCommandsHandler;
-
 - (instancetype)init NS_DESIGNATED_INITIALIZER;
 
 - (instancetype)initWithStyle:(UITableViewStyle)style NS_UNAVAILABLE;

ios/chrome/browser/ui/settings/about_chrome_table_view_controller.mm

@@ -168,14 +168,14 @@ - (void)didTapVersionFooter:(VersionFooter*)footer {
   MDCSnackbarMessage* message =
       [MDCSnackbarMessage messageWithText:messageText];
   message.category = @"version copied";
-  [self.snackbarCommandsHandler showSnackbarMessage:message bottomOffset:0];
+  [self.snackbarHandler showSnackbarMessage:message bottomOffset:0];
 }
 
 #pragma mark - Private methods
 
 - (void)openURL:(GURL)URL {
   OpenNewTabCommand* command = [OpenNewTabCommand commandWithURLFromChrome:URL];
-  [self.applicationCommandsHandler closeSettingsUIAndOpenURL:command];
+  [self.applicationHandler closeSettingsUIAndOpenURL:command];
 }
 
 - (std::string)versionString {

ios/chrome/browser/ui/settings/autofill/autofill_credit_card_edit_table_view_controller.mm

@@ -101,7 +101,7 @@ - (void)editButtonPressed {
     GURL paymentsURL = autofill::payments::GetManageInstrumentsUrl();
     OpenNewTabCommand* command =
         [OpenNewTabCommand commandWithURLFromChrome:paymentsURL];
-    [self.dispatcher closeSettingsUIAndOpenURL:command];
+    [self.applicationHandler closeSettingsUIAndOpenURL:command];
 
     // Don't call [super editButtonPressed] because edit mode is not actually
     // entered in this case.

ios/chrome/browser/ui/settings/autofill/autofill_credit_card_table_view_controller.mm

@@ -445,7 +445,7 @@ - (void)tableView:(UITableView*)tableView
       [[AutofillCreditCardEditTableViewController alloc]
            initWithCreditCard:*creditCards[indexPath.item]
           personalDataManager:_personalDataManager];
-  controller.dispatcher = self.dispatcher;
+  [self configureHandlersForRootViewController:controller];
   [self.navigationController pushViewController:controller animated:YES];
 }
 

ios/chrome/browser/ui/settings/content_settings/content_settings_table_view_controller.mm

@@ -402,7 +402,7 @@ - (void)tableView:(UITableView*)tableView
       BlockPopupsTableViewController* controller =
           [[BlockPopupsTableViewController alloc]
               initWithBrowserState:_browser->GetBrowserState()];
-      controller.dispatcher = self.dispatcher;
+      [self configureHandlersForRootViewController:controller];
       [self.navigationController pushViewController:controller animated:YES];
       break;
     }

ios/chrome/browser/ui/settings/google_services/accounts_table_view_controller.mm

@@ -977,11 +977,7 @@ - (void)openPassphraseDialog {
   // Verify that the accounts table is displayed from a navigation controller.
   DCHECK(self.navigationController);
 
-  // TODO(crbug.com/1045047): Use HandlerForProtocol after commands protocol
-  // clean up.
-  controllerToPush.dispatcher = static_cast<
-      id<ApplicationCommands, BrowserCommands, BrowsingDataCommands>>(
-      _browser->GetCommandDispatcher());
+  [self configureHandlersForRootViewController:controllerToPush];
   [self.navigationController pushViewController:controllerToPush animated:YES];
 }
 

ios/chrome/browser/ui/settings/google_services/google_services_settings_coordinator.mm

@@ -16,10 +16,12 @@
 #import "ios/chrome/browser/shared/model/browser_state/chrome_browser_state.h"
 #import "ios/chrome/browser/shared/model/url/chrome_url_constants.h"
 #import "ios/chrome/browser/shared/public/commands/application_commands.h"
+#import "ios/chrome/browser/shared/public/commands/browser_commands.h"
 #import "ios/chrome/browser/shared/public/commands/browsing_data_commands.h"
 #import "ios/chrome/browser/shared/public/commands/command_dispatcher.h"
 #import "ios/chrome/browser/shared/public/commands/open_new_tab_command.h"
 #import "ios/chrome/browser/shared/public/commands/show_signin_command.h"
+#import "ios/chrome/browser/shared/public/commands/snackbar_commands.h"
 #import "ios/chrome/browser/shared/public/features/features.h"
 #import "ios/chrome/browser/shared/ui/table_view/table_view_utils.h"
 #import "ios/chrome/browser/signin/authentication_service.h"
@@ -98,9 +100,19 @@ - (void)start {
   self.mediator.commandHandler = self;
   viewController.modelDelegate = self.mediator;
   viewController.serviceDelegate = self.mediator;
-  viewController.dispatcher = static_cast<
-      id<ApplicationCommands, BrowserCommands, BrowsingDataCommands>>(
-      self.browser->GetCommandDispatcher());
+
+  CommandDispatcher* dispatcher = self.browser->GetCommandDispatcher();
+  viewController.applicationHandler =
+      HandlerForProtocol(dispatcher, ApplicationCommands);
+  viewController.browserHandler =
+      HandlerForProtocol(dispatcher, BrowserCommands);
+  viewController.browsingDataHandler =
+      HandlerForProtocol(dispatcher, BrowsingDataCommands);
+  viewController.settingsHandler =
+      HandlerForProtocol(dispatcher, ApplicationSettingsCommands);
+  viewController.snackbarHandler =
+      HandlerForProtocol(dispatcher, SnackbarCommands);
+
   DCHECK(self.baseNavigationController);
   [self.baseNavigationController pushViewController:self.viewController
                                            animated:YES];

ios/chrome/browser/ui/settings/google_services/manage_sync_settings_coordinator.mm

@@ -22,10 +22,12 @@
 #import "ios/chrome/browser/shared/model/browser_state/chrome_browser_state.h"
 #import "ios/chrome/browser/shared/model/url/chrome_url_constants.h"
 #import "ios/chrome/browser/shared/public/commands/application_commands.h"
+#import "ios/chrome/browser/shared/public/commands/browser_commands.h"
 #import "ios/chrome/browser/shared/public/commands/browsing_data_commands.h"
 #import "ios/chrome/browser/shared/public/commands/command_dispatcher.h"
 #import "ios/chrome/browser/shared/public/commands/open_new_tab_command.h"
 #import "ios/chrome/browser/shared/public/commands/show_signin_command.h"
+#import "ios/chrome/browser/shared/public/commands/snackbar_commands.h"
 #import "ios/chrome/browser/shared/ui/symbols/chrome_icon.h"
 #import "ios/chrome/browser/shared/ui/table_view/table_view_utils.h"
 #import "ios/chrome/browser/signin/authentication_service.h"
@@ -151,25 +153,35 @@ - (void)start {
   UITableViewStyle style = _accountState == SyncSettingsAccountState::kSignedIn
                                ? UITableViewStyleInsetGrouped
                                : ChromeTableViewStyle();
-  self.viewController =
+  ManageSyncSettingsTableViewController* viewController =
       [[ManageSyncSettingsTableViewController alloc] initWithStyle:style];
+  self.viewController = viewController;
 
   NSString* title = self.mediator.overrideViewControllerTitle;
   if (!title) {
     title = self.delegate.manageSyncSettingsCoordinatorTitle;
   }
-  self.viewController.title = title;
-  self.viewController.isAccountStateSignedIn =
+  viewController.title = title;
+  viewController.isAccountStateSignedIn =
       _accountState == SyncSettingsAccountState::kSignedIn;
-  self.viewController.serviceDelegate = self.mediator;
-  self.viewController.presentationDelegate = self;
-  self.viewController.modelDelegate = self.mediator;
-  self.viewController.dispatcher = static_cast<
-      id<ApplicationCommands, BrowserCommands, BrowsingDataCommands>>(
-      self.browser->GetCommandDispatcher());
-
-  self.mediator.consumer = self.viewController;
-  [self.baseNavigationController pushViewController:self.viewController
+  viewController.serviceDelegate = self.mediator;
+  viewController.presentationDelegate = self;
+  viewController.modelDelegate = self.mediator;
+
+  CommandDispatcher* dispatcher = self.browser->GetCommandDispatcher();
+  viewController.applicationHandler =
+      HandlerForProtocol(dispatcher, ApplicationCommands);
+  viewController.browserHandler =
+      HandlerForProtocol(dispatcher, BrowserCommands);
+  viewController.browsingDataHandler =
+      HandlerForProtocol(dispatcher, BrowsingDataCommands);
+  viewController.settingsHandler =
+      HandlerForProtocol(dispatcher, ApplicationSettingsCommands);
+  viewController.snackbarHandler =
+      HandlerForProtocol(dispatcher, SnackbarCommands);
+
+  self.mediator.consumer = viewController;
+  [self.baseNavigationController pushViewController:viewController
                                            animated:YES];
   _syncObserver = std::make_unique<SyncObserverBridge>(self, self.syncService);
 }
@@ -394,11 +406,8 @@ - (void)openPassphraseDialog {
     controllerToPush = [[SyncEncryptionTableViewController alloc]
         initWithBrowser:self.browser];
   }
-  // TODO(crbug.com/1045047): Use HandlerForProtocol after commands protocol
-  // clean up.
-  controllerToPush.dispatcher = static_cast<
-      id<ApplicationCommands, BrowserCommands, BrowsingDataCommands>>(
-      self.browser->GetCommandDispatcher());
+
+  [self.viewController configureHandlersForRootViewController:controllerToPush];
   [self.baseNavigationController pushViewController:controllerToPush
                                            animated:YES];
 }

ios/chrome/browser/ui/settings/password/password_settings/BUILD.gn

@@ -120,6 +120,7 @@ source_set("unit_tests") {
     "//ios/chrome/common/ui/reauthentication",
     "//ios/chrome/test:test_support",
     "//ios/chrome/test/app:test_support",
+    "//ios/testing:protocol_fake",
     "//ios/web/public/test",
     "//testing/gmock",
     "//testing/gtest",

ios/chrome/browser/ui/settings/password/password_settings/password_settings_coordinator.mm

@@ -442,11 +442,12 @@ - (void)showMovedToAccountSnackbarWithPasswordCount:(int)count
       pattern, "COUNT", count, "EMAIL", base::UTF8ToUTF16(email));
 
   TriggerHapticFeedbackForNotification(UINotificationFeedbackTypeSuccess);
-  [self.handlerForSnackbarCommands
-      showSnackbarWithMessage:base::SysUTF16ToNSString(result)
-                   buttonText:nil
-                messageAction:nil
-             completionAction:nil];
+  id<SnackbarCommands> handler = HandlerForProtocol(
+      self.browser->GetCommandDispatcher(), SnackbarCommands);
+  [handler showSnackbarWithMessage:base::SysUTF16ToNSString(result)
+                        buttonText:nil
+                     messageAction:nil
+                  completionAction:nil];
 }
 
 #pragma mark - PasswordExportHandler
@@ -559,22 +560,6 @@ - (void)settingsWasDismissed {
   [self.delegate passwordSettingsCoordinatorDidRemove:self];
 }
 
-- (id<ApplicationCommands, BrowserCommands, BrowsingDataCommands>)
-    handlerForSettings {
-  NOTREACHED();
-  return nil;
-}
-
-- (id<ApplicationCommands>)handlerForApplicationCommands {
-  NOTREACHED();
-  return nil;
-}
-
-- (id<SnackbarCommands>)handlerForSnackbarCommands {
-  return HandlerForProtocol(self.browser->GetCommandDispatcher(),
-                            SnackbarCommands);
-}
-
 #pragma mark - ReauthenticationCoordinatorDelegate
 
 - (void)successfulReauthenticationWithCoordinator: