[iOS][multiball] Move WebStateList observation to Scene level.

MainController observes WSL to know when the last {normal|incognito}
tab is closed. Conceptually, this seems like a Scene-level concern.
However, clearing browsing data might be an App-level concept, so I
keep the logic in MainController for now.

Bug: none
Change-Id: I0b3453518f4f0390a34f77ce27817f4af1f4d650
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2003135
Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
Reviewed-by: Mark Cogan <marq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#733390}

ios/chrome/app/main_controller.mm

@@ -276,8 +276,7 @@ void MainControllerAuthenticationServiceDelegate::ClearBrowsingData(
 }  // namespace
 
 @interface MainController () <BrowserStateStorageSwitching,
-                              PrefObserverDelegate,
-                              WebStateListObserving> {
+                              PrefObserverDelegate> {
   IBOutlet UIWindow* _window;
 
   // Weak; owned by the ChromeBrowserProvider.
@@ -346,14 +345,8 @@ void MainControllerAuthenticationServiceDelegate::ClearBrowsingData(
 // browser has started up to the FOREGROUND stage.
 @property(nonatomic, readonly) TabGridCoordinator* mainCoordinator;
 
-// Shows the tab switcher UI.
-- (void)showTabSwitcher;
 // Starts a voice search on the current BVC.
 - (void)startVoiceSearchInCurrentBVC;
-// Called when the last incognito tab was closed.
-- (void)lastIncognitoTabClosed;
-// Called when the last regular tab was closed.
-- (void)lastRegularTabClosed;
 // Returns whether the restore infobar should be displayed.
 - (bool)mustShowRestoreInfobar;
 // Switch all global states for the given mode (normal or incognito).
@@ -412,11 +405,6 @@ void MainControllerAuthenticationServiceDelegate::ClearBrowsingData(
 - (void)scheduleShowPromo;
 // Crashes the application if requested.
 - (void)crashIfRequested;
-// Clears incognito data that is specific to iOS and won't be cleared by
-// deleting the browser state.
-- (void)clearIOSSpecificIncognitoData;
-// Destroys and rebuilds the incognito browser state.
-- (void)destroyAndRebuildIncognitoBrowserState;
 // Handles the notification that first run modal dialog UI is about to complete.
 - (void)handleFirstRunUIWillFinish;
 // Handles the notification that first run modal dialog UI completed.
@@ -603,7 +591,7 @@ void MainControllerAuthenticationServiceDelegate::ClearBrowsingData(
   [self.browserViewWrangler shutdown];
   self.browserViewWrangler = [[BrowserViewWrangler alloc]
              initWithBrowserState:self.mainBrowserState
-             webStateListObserver:self
+             webStateListObserver:self.sceneController
        applicationCommandEndpoint:self.sceneController
       browsingDataCommandEndpoint:self
              appURLLoadingService:self.appURLLoadingService
@@ -640,7 +628,7 @@ void MainControllerAuthenticationServiceDelegate::ClearBrowsingData(
   BOOL switchFromIncognito = startInIncognito && ![self canLaunchInIncognito];
 
   if (postCrashLaunch || switchFromIncognito) {
-    [self clearIOSSpecificIncognitoData];
+    [self.sceneController clearIOSSpecificIncognitoData];
     if (switchFromIncognito)
       [self switchGlobalStateToMode:ApplicationMode::NORMAL];
   }
@@ -739,54 +727,6 @@ void MainControllerAuthenticationServiceDelegate::ClearBrowsingData(
       triggerSystemPromptForNewUser:YES];
 }
 
-- (void)clearIOSSpecificIncognitoData {
-  DCHECK(self.mainBrowserState->HasOffTheRecordChromeBrowserState());
-  ios::ChromeBrowserState* otrBrowserState =
-      self.mainBrowserState->GetOffTheRecordChromeBrowserState();
-  [self removeBrowsingDataForBrowserState:otrBrowserState
-                               timePeriod:browsing_data::TimePeriod::ALL_TIME
-                               removeMask:BrowsingDataRemoveMask::REMOVE_ALL
-                          completionBlock:^{
-                            [self activateBVCAndMakeCurrentBVCPrimary];
-                          }];
-}
-
-- (void)destroyAndRebuildIncognitoBrowserState {
-  BOOL otrBVCIsCurrent = (self.currentBVC == self.otrBVC);
-
-  // Clear the OTR tab model and notify the _tabSwitcher that its otrBVC will
-  // be destroyed.
-  [_tabSwitcher setOtrBrowser:nil];
-
-  [self.browserViewWrangler destroyAndRebuildIncognitoBrowser];
-
-  if (otrBVCIsCurrent) {
-    [self activateBVCAndMakeCurrentBVCPrimary];
-  }
-
-  // Always set the new otr browser for the tablet or grid switcher.
-  // Notify the _tabSwitcher with the new otrBVC.
-  [_tabSwitcher setOtrBrowser:self.mainBrowser];
-
-  // This seems the best place to deem the destroying and rebuilding the
-  // incognito browser state to be completed.
-  breakpad_helper::SetDestroyingAndRebuildingIncognitoBrowserState(
-      /*in_progress=*/false);
-}
-
-- (void)activateBVCAndMakeCurrentBVCPrimary {
-  // If there are pending removal operations, the activation will be deferred
-  // until the callback is received.
-  BrowsingDataRemover* browsingDataRemover =
-      BrowsingDataRemoverFactory::GetForBrowserStateIfExists(
-          self.currentBrowserState);
-  if (browsingDataRemover && browsingDataRemover->IsRemoving())
-    return;
-
-  self.interfaceProvider.mainInterface.userInteractionEnabled = YES;
-  self.interfaceProvider.incognitoInterface.userInteractionEnabled = YES;
-  [self.currentBVC setPrimary:YES];
-}
 
 #pragma mark - Property implementation.
 
@@ -1452,54 +1392,6 @@ void MainControllerAuthenticationServiceDelegate::ClearBrowsingData(
 
 
 
-#pragma mark - Tab closure handlers
-
-- (void)lastIncognitoTabClosed {
-  // This seems the best place to mark the start of destroying the incognito
-  // browser state.
-  breakpad_helper::SetDestroyingAndRebuildingIncognitoBrowserState(
-      /*in_progress=*/true);
-  DCHECK(self.mainBrowserState->HasOffTheRecordChromeBrowserState());
-  [self clearIOSSpecificIncognitoData];
-
-  // OffTheRecordProfileIOData cannot be deleted before all the requests are
-  // deleted. Queue browser state recreation on IO thread.
-  base::PostTaskAndReply(FROM_HERE, {web::WebThread::IO}, base::DoNothing(),
-                         base::BindRepeating(^{
-                           [self destroyAndRebuildIncognitoBrowserState];
-                         }));
-
-  // a) The first condition can happen when the last incognito tab is closed
-  // from the tab switcher.
-  // b) The second condition can happen if some other code (like JS) triggers
-  // closure of tabs from the otr tab model when it's not current.
-  // Nothing to do here. The next user action (like clicking on an existing
-  // regular tab or creating a new incognito tab from the settings menu) will
-  // take care of the logic to mode switch.
-  if (self.tabSwitcherIsActive || ![self.currentTabModel isOffTheRecord]) {
-    return;
-  }
-
-  if ([self.currentTabModel count] == 0U) {
-    [self showTabSwitcher];
-  } else {
-    [self.sceneController setCurrentInterfaceForMode:ApplicationMode::NORMAL];
-  }
-}
-
-- (void)lastRegularTabClosed {
-  // a) The first condition can happen when the last regular tab is closed from
-  // the tab switcher.
-  // b) The second condition can happen if some other code (like JS) triggers
-  // closure of tabs from the main tab model when the main tab model is not
-  // current.
-  // Nothing to do here.
-  if (self.tabSwitcherIsActive || [self.currentTabModel isOffTheRecord]) {
-    return;
-  }
-
-  [self showTabSwitcher];
-}
 
 #pragma mark - Mode Switching
 
@@ -1542,39 +1434,6 @@ void MainControllerAuthenticationServiceDelegate::ClearBrowsingData(
   return self.currentBVC.browserState;
 }
 
-- (void)showTabSwitcher {
-  DCHECK(_tabSwitcher);
-  // Tab switcher implementations may need to rebuild state before being
-  // displayed.
-  [_tabSwitcher restoreInternalStateWithMainTabModel:self.mainTabModel
-                                         otrTabModel:self.otrTabModel
-                                      activeTabModel:self.currentTabModel];
-  self.tabSwitcherIsActive = YES;
-  [_tabSwitcher setDelegate:self.sceneController];
-
-  [self.mainCoordinator showTabSwitcher:_tabSwitcher];
-}
-
-#pragma mark - WebStateListObserving
-
-// Called when a WebState is removed. Triggers the switcher view when the last
-// WebState is closed on a device that uses the switcher.
-- (void)webStateList:(WebStateList*)notifiedWebStateList
-    didDetachWebState:(web::WebState*)webState
-              atIndex:(int)atIndex {
-  // Do nothing on initialization.
-  if (![self currentTabModel].webStateList)
-    return;
-
-  if (notifiedWebStateList->empty()) {
-    if (webState->GetBrowserState()->IsOffTheRecord()) {
-      [self lastIncognitoTabClosed];
-    } else {
-      [self lastRegularTabClosed];
-    }
-  }
-}
-
 #pragma mark - Tab opening utility methods.
 
 - (ProceduralBlock)completionBlockForTriggeringAction:

ios/chrome/app/main_controller_guts.h

@@ -7,12 +7,16 @@
 
 #import <UIKit/UIKit.h>
 
+#import "base/ios/block_types.h"
+#include "components/browsing_data/core/browsing_data_utils.h"
 #include "ios/chrome/app/startup/chrome_app_startup_parameters.h"
+#include "ios/chrome/browser/browsing_data/browsing_data_remove_mask.h"
 #import "ios/chrome/browser/crash_report/crash_restore_helper.h"
 #import "ios/chrome/browser/ui/settings/settings_navigation_controller.h"
 #import "ios/public/provider/chrome/browser/user_feedback/user_feedback_provider.h"
 
 @class BrowserViewController;
+@class BrowserViewWrangler;
 @class HistoryCoordinator;
 @class SigninInteractionCoordinator;
 @class TabGridCoordinator;
@@ -91,9 +95,9 @@ enum class TabSwitcherDismissalMode { NONE, NORMAL, INCOGNITO };
 // Keeps track of the restore state during startup.
 @property(nonatomic, strong) CrashRestoreHelper* restoreHelper;
 
+- (BrowserViewWrangler*)browserViewWrangler;
 - (id<TabSwitcher>)tabSwitcher;
 - (TabModel*)currentTabModel;
-- (id<TabSwitcher>)tabSwitcher;
 - (ios::ChromeBrowserState*)mainBrowserState;
 - (ios::ChromeBrowserState*)currentBrowserState;
 - (BrowserViewController*)currentBVC;
@@ -102,14 +106,14 @@ enum class TabSwitcherDismissalMode { NONE, NORMAL, INCOGNITO };
 - (TabGridCoordinator*)mainCoordinator;
 - (id<BrowserInterfaceProvider>)interfaceProvider;
 - (void)startVoiceSearchInCurrentBVC;
-- (void)showTabSwitcher;
 
 // Sets |currentBVC| as the root view controller for the window.
 - (void)displayCurrentBVCAndFocusOmnibox:(BOOL)focusOmnibox;
 
-// Activates |mainBVC| and |otrBVC| and sets |currentBVC| as primary iff
-// |currentBVC| can be made active.
-- (void)activateBVCAndMakeCurrentBVCPrimary;
+- (void)removeBrowsingDataForBrowserState:(ios::ChromeBrowserState*)browserState
+                               timePeriod:(browsing_data::TimePeriod)timePeriod
+                               removeMask:(BrowsingDataRemoveMask)removeMask
+                          completionBlock:(ProceduralBlock)completionBlock;
 
 @end
 

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

@@ -10,6 +10,7 @@ source_set("scene_guts") {
     "//ios/chrome/app/application_delegate:application_delegate_internal",
     "//ios/chrome/browser:utils",
     "//ios/chrome/browser/url_loading",
+    "//ios/chrome/browser/web_state_list",
   ]
 
   libs = [ "UIKit.framework" ]
@@ -39,6 +40,7 @@ source_set("scene") {
     "//ios/chrome/browser:chrome_url_constants",
     "//ios/chrome/browser/browser_state",
     "//ios/chrome/browser/browsing_data",
+    "//ios/chrome/browser/crash_report",
     "//ios/chrome/browser/main",
     "//ios/chrome/browser/ntp:features",
     "//ios/chrome/browser/payments",

ios/chrome/browser/ui/main/scene_controller.mm

@@ -8,6 +8,7 @@
 #include "base/metrics/histogram_functions.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/strings/sys_string_conversions.h"
+#include "base/task/post_task.h"
 #include "components/payments/core/features.h"
 #include "components/signin/public/identity_manager/identity_manager.h"
 #include "components/url_formatter/url_formatter.h"
@@ -23,6 +24,7 @@
 #include "ios/chrome/browser/browsing_data/browsing_data_remover_factory.h"
 #include "ios/chrome/browser/chrome_url_constants.h"
 #import "ios/chrome/browser/chrome_url_util.h"
+#include "ios/chrome/browser/crash_report/breakpad_helper.h"
 #include "ios/chrome/browser/main/browser.h"
 #include "ios/chrome/browser/ntp/features.h"
 #include "ios/chrome/browser/payments/ios_payment_instrument_launcher.h"
@@ -39,6 +41,7 @@
 #import "ios/chrome/browser/ui/commands/show_signin_command.h"
 #include "ios/chrome/browser/ui/history/history_coordinator.h"
 #import "ios/chrome/browser/ui/main/browser_interface_provider.h"
+#import "ios/chrome/browser/ui/main/browser_view_wrangler.h"
 #import "ios/chrome/browser/ui/settings/settings_navigation_controller.h"
 #import "ios/chrome/browser/ui/signin_interaction/signin_interaction_coordinator.h"
 #include "ios/chrome/browser/ui/tab_grid/tab_grid_coordinator.h"
@@ -50,10 +53,12 @@
 #import "ios/chrome/browser/url_loading/url_loading_service.h"
 #import "ios/chrome/browser/url_loading/url_loading_service_factory.h"
 #import "ios/chrome/browser/web_state_list/web_state_list.h"
+#import "ios/chrome/browser/web_state_list/web_state_list_observer_bridge.h"
 #include "ios/public/provider/chrome/browser/chrome_browser_provider.h"
 #include "ios/public/provider/chrome/browser/mailto/mailto_handler_provider.h"
 #include "ios/public/provider/chrome/browser/signin/chrome_identity_service.h"
 #import "ios/public/provider/chrome/browser/user_feedback/user_feedback_provider.h"
+#include "ios/web/public/thread/web_task_traits.h"
 #import "ios/web/public/web_state.h"
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
@@ -90,7 +95,8 @@ enum class EnterTabSwitcherSnapshotResult {
 }  // namespace
 
 @interface SceneController () <UserFeedbackDataSource,
-                               SettingsNavigationControllerDelegate>
+                               SettingsNavigationControllerDelegate,
+                               WebStateListObserving>
 
 // A flag that keeps track of the UI initialization for the controlled scene.
 @property(nonatomic, assign) BOOL hasInitializedUI;
@@ -217,7 +223,7 @@ enum class EnterTabSwitcherSnapshotResult {
   DCHECK(!self.mainController.isTabSwitcherActive);
   if (!self.mainController.isProcessingVoiceSearchCommand) {
     [self.mainController.currentBVC userEnteredTabSwitcher];
-    [self.mainController showTabSwitcher];
+    [self showTabSwitcher];
     self.mainController.isProcessingTabSwitcherCommand = YES;
     dispatch_after(dispatch_time(DISPATCH_TIME_NOW,
                                  kExpectedTransitionDurationInNanoSeconds),
@@ -635,7 +641,7 @@ enum class EnterTabSwitcherSnapshotResult {
     self.mainController.modeToDisplayOnTabSwitcherDismissal =
         TabSwitcherDismissalMode::NONE;
     self.mainController.NTPActionAfterTabSwitcherDismissal = NO_ACTION;
-    [self.mainController showTabSwitcher];
+    [self showTabSwitcher];
     return;
   }
 
@@ -827,7 +833,7 @@ enum class EnterTabSwitcherSnapshotResult {
     [self.mainController displayCurrentBVCAndFocusOmnibox:NO];
 
   // Tell the BVC that was made current that it can use the web.
-  [self.mainController activateBVCAndMakeCurrentBVCPrimary];
+  [self activateBVCAndMakeCurrentBVCPrimary];
 }
 
 - (void)dismissModalDialogsWithCompletion:(ProceduralBlock)completion
@@ -1151,4 +1157,144 @@ enum class EnterTabSwitcherSnapshotResult {
       self.mainController.mainCoordinator.viewController);
 }
 
+#pragma mark - WebStateListObserving
+
+// Called when a WebState is removed. Triggers the switcher view when the last
+// WebState is closed on a device that uses the switcher.
+- (void)webStateList:(WebStateList*)notifiedWebStateList
+    didDetachWebState:(web::WebState*)webState
+              atIndex:(int)atIndex {
+  // Do nothing on initialization.
+  if (![self currentTabModel].webStateList)
+    return;
+
+  if (notifiedWebStateList->empty()) {
+    if (webState->GetBrowserState()->IsOffTheRecord()) {
+      [self lastIncognitoTabClosed];
+    } else {
+      [self lastRegularTabClosed];
+    }
+  }
+}
+
+// Called when the last incognito tab was closed.
+- (void)lastIncognitoTabClosed {
+  // This seems the best place to mark the start of destroying the incognito
+  // browser state.
+  breakpad_helper::SetDestroyingAndRebuildingIncognitoBrowserState(
+      /*in_progress=*/true);
+  DCHECK(self.mainController.mainBrowserState
+             ->HasOffTheRecordChromeBrowserState());
+  [self clearIOSSpecificIncognitoData];
+
+  // OffTheRecordProfileIOData cannot be deleted before all the requests are
+  // deleted. Queue browser state recreation on IO thread.
+  base::PostTaskAndReply(FROM_HERE, {web::WebThread::IO}, base::DoNothing(),
+                         base::BindRepeating(^{
+                           [self destroyAndRebuildIncognitoBrowserState];
+                         }));
+
+  // a) The first condition can happen when the last incognito tab is closed
+  // from the tab switcher.
+  // b) The second condition can happen if some other code (like JS) triggers
+  // closure of tabs from the otr tab model when it's not current.
+  // Nothing to do here. The next user action (like clicking on an existing
+  // regular tab or creating a new incognito tab from the settings menu) will
+  // take care of the logic to mode switch.
+  if (self.mainController.tabSwitcherIsActive ||
+      ![self.mainController.currentTabModel isOffTheRecord]) {
+    return;
+  }
+
+  if ([self.mainController.currentTabModel count] == 0U) {
+    [self showTabSwitcher];
+  } else {
+    [self setCurrentInterfaceForMode:ApplicationMode::NORMAL];
+  }
+}
+
+// Called when the last regular tab was closed.
+- (void)lastRegularTabClosed {
+  // a) The first condition can happen when the last regular tab is closed from
+  // the tab switcher.
+  // b) The second condition can happen if some other code (like JS) triggers
+  // closure of tabs from the main tab model when the main tab model is not
+  // current.
+  // Nothing to do here.
+  if (self.mainController.tabSwitcherIsActive ||
+      [self.mainController.currentTabModel isOffTheRecord]) {
+    return;
+  }
+
+  [self showTabSwitcher];
+}
+
+- (void)clearIOSSpecificIncognitoData {
+  DCHECK(self.mainController.mainBrowserState
+             ->HasOffTheRecordChromeBrowserState());
+  ios::ChromeBrowserState* otrBrowserState =
+      self.mainController.mainBrowserState->GetOffTheRecordChromeBrowserState();
+  [self.mainController
+      removeBrowsingDataForBrowserState:otrBrowserState
+                             timePeriod:browsing_data::TimePeriod::ALL_TIME
+                             removeMask:BrowsingDataRemoveMask::REMOVE_ALL
+                        completionBlock:^{
+                          [self activateBVCAndMakeCurrentBVCPrimary];
+                        }];
+}
+
+- (void)activateBVCAndMakeCurrentBVCPrimary {
+  // If there are pending removal operations, the activation will be deferred
+  // until the callback is received.
+  BrowsingDataRemover* browsingDataRemover =
+      BrowsingDataRemoverFactory::GetForBrowserStateIfExists(
+          self.currentBrowserState);
+  if (browsingDataRemover && browsingDataRemover->IsRemoving())
+    return;
+
+  self.interfaceProvider.mainInterface.userInteractionEnabled = YES;
+  self.interfaceProvider.incognitoInterface.userInteractionEnabled = YES;
+  [self.mainController.currentBVC setPrimary:YES];
+}
+
+- (void)showTabSwitcher {
+  DCHECK(self.mainController.tabSwitcher);
+  // Tab switcher implementations may need to rebuild state before being
+  // displayed.
+  [self.mainController.tabSwitcher
+      restoreInternalStateWithMainTabModel:self.mainInterface.tabModel
+                               otrTabModel:self.incognitoInterface.tabModel
+                            activeTabModel:self.currentTabModel];
+  self.mainController.tabSwitcherIsActive = YES;
+  [self.mainController.tabSwitcher setDelegate:self];
+
+  [self.mainController.mainCoordinator
+      showTabSwitcher:self.mainController.tabSwitcher];
+}
+
+// Destroys and rebuilds the incognito browser state.
+- (void)destroyAndRebuildIncognitoBrowserState {
+  BOOL otrBVCIsCurrent = (self.interfaceProvider.mainInterface.bvc ==
+                          self.interfaceProvider.incognitoInterface.bvc);
+
+  // Clear the OTR tab model and notify the _tabSwitcher that its otrBVC will
+  // be destroyed.
+  [self.mainController.tabSwitcher setOtrBrowser:nil];
+
+  [self.mainController.browserViewWrangler destroyAndRebuildIncognitoBrowser];
+
+  if (otrBVCIsCurrent) {
+    [self activateBVCAndMakeCurrentBVCPrimary];
+  }
+
+  // Always set the new otr tab model for the tablet or grid switcher.
+  // Notify the _tabSwitcher with the new otrBVC.
+  [self.mainController.tabSwitcher setOtrBrowser:self.mainInterface.browser];
+
+  // This seems the best place to deem the destroying and rebuilding the
+  // incognito browser state to be completed.
+  breakpad_helper::SetDestroyingAndRebuildingIncognitoBrowserState(
+      /*in_progress=*/false);
+}
+
 @end

ios/chrome/browser/ui/main/scene_controller_guts.h

@@ -11,6 +11,7 @@
 #import "ios/chrome/app/application_delegate/tab_opening.h"
 #import "ios/chrome/browser/procedural_block_types.h"
 #import "ios/chrome/browser/url_loading/url_loading_params.h"
+#import "ios/chrome/browser/web_state_list/web_state_list_observer_bridge.h"
 
 @class TabModel;
 
@@ -18,7 +19,7 @@ namespace ios {
 class ChromeBrowserState;
 }  // namespace ios
 
-@protocol SceneControllerGuts
+@protocol SceneControllerGuts <WebStateListObserving>
 
 - (void)dismissModalDialogsWithCompletion:(ProceduralBlock)completion
                            dismissOmnibox:(BOOL)dismissOmnibox;
@@ -62,6 +63,12 @@ class ChromeBrowserState;
 // Returns YES if the settings navigation controller exists.
 - (BOOL)hasSettingsNavigationController;
 
+// Clears incognito data that is specific to iOS and won't be cleared by
+// deleting the browser state.
+- (void)clearIOSSpecificIncognitoData;
+
+- (void)activateBVCAndMakeCurrentBVCPrimary;
+
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_MAIN_SCENE_CONTROLLER_GUTS_H_