[multiball] Move ApplicationCommands to SceneController.

Introduces a temporary interface connecting the Scene and the Main
controllers, and exposes a bunch of internals of MainController through
a MainControllerGuts protocol (obviously temporary).

Uses this interface to implement ApplicationCommands in SceneController
and updates the use of the commands endpoint to be SceneController.

Note also:
- Updates a bunch of ivar use in MainController to properties.
- Moves a Deferred Initialization constant to a shared file as it's
used in both SceneCtrl and MainCtrl. It seems like this is semantically
correct for it to be used in both places, so it probably is a permanent
change.
- Removes a DCHECK(_localStatePrefObserverBridge) in
showSettingsFromViewController, as keeping it would mean exposing MainController->_localStatePrefObserverBridge to SceneController.

Bug: None
Change-Id: Idd45bc0850eaabca068e59e3843d901c9a0c780b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1845976
Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
Reviewed-by: Mark Cogan <marq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709497}

ios/chrome/app/deferred_initialization_runner.h

@@ -9,6 +9,9 @@
 
 #include "base/ios/block_types.h"
 
+// Constants for deferred initialization of preferences observer.
+extern NSString* const kPrefObserverInit;
+
 // A singleton object to run initialization code asynchronously. Blocks are
 // scheduled to be run after a delay. The block is named when added to the
 // singleton so that other code can force a deferred block to be run

ios/chrome/app/deferred_initialization_runner.mm

@@ -13,6 +13,8 @@
 #error "This file requires ARC support."
 #endif
 
+NSString* const kPrefObserverInit = @"PrefObserverInit";
+
 // An object encapsulating the deferred execution of a block of initialization
 // code.
 @interface DeferredInitializationBlock : NSObject

ios/chrome/app/main_application_delegate.mm

@@ -86,6 +86,10 @@
       _sceneState = [[SceneState alloc] init];
       _sceneController =
           [[SceneController alloc] initWithSceneState:_sceneState];
+
+      // This is temporary plumbing that's not supposed to be here.
+      _sceneController.mainController = (id<MainControllerGuts>)_mainController;
+      _mainController.sceneController = _sceneController;
     }
   }
   return self;
@@ -117,8 +121,14 @@
 
   BOOL inBackground =
       [application applicationState] == UIApplicationStateBackground;
-  return [_appState requiresHandlingAfterLaunchWithOptions:launchOptions
-                                           stateBackground:inBackground];
+  BOOL requiresHandling =
+      [_appState requiresHandlingAfterLaunchWithOptions:launchOptions
+                                        stateBackground:inBackground];
+  if (!IsMultiwindowSupported()) {
+    self.sceneState.activationLevel = SceneActivationLevelForegroundInactive;
+  }
+
+  return requiresHandling;
 }
 
 - (void)applicationDidBecomeActive:(UIApplication*)application {
@@ -152,10 +162,10 @@
     self.sceneState.activationLevel = SceneActivationLevelBackground;
   }
 
-  [_appState
-      applicationDidEnterBackground:application
-                       memoryHelper:_memoryHelper
-            incognitoContentVisible:_mainController.incognitoContentVisible];
+  [_appState applicationDidEnterBackground:application
+                              memoryHelper:_memoryHelper
+                   incognitoContentVisible:self.sceneController
+                                               .incognitoContentVisible];
 }
 
 // Called when returning to the foreground.

ios/chrome/app/main_controller.h

@@ -24,8 +24,7 @@
 //
 // By design, it has no public API of its own. Anything interacting with
 // MainController should be doing so through a specific protocol.
-@interface MainController : NSObject <ApplicationCommands,
-                                      AppNavigation,
+@interface MainController : NSObject <AppNavigation,
                                       BrowserLauncher,
                                       MainControllerGuts,
                                       StartupInformation,
@@ -43,9 +42,8 @@
 // to the user preferences.
 @property(nonatomic, weak) MetricsMediator* metricsMediator;
 
-// Returns whether the app is showing or partially showing the
-// incognito panel.
-@property(nonatomic, assign, readonly) BOOL incognitoContentVisible;
+// For temporary plumbing only.
+@property(nonatomic, weak) id<ApplicationCommands> sceneController;
 
 @end
 

ios/chrome/app/main_controller_guts.h

@@ -10,6 +10,7 @@
 #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 HistoryCoordinator;
 @class SigninInteractionCoordinator;
 @class TabGridCoordinator;

ios/chrome/browser/metrics/tab_usage_recorder_test_util.mm

@@ -80,7 +80,7 @@ bool OpenNewIncognitoTabUsingUIAndEvictMainTabs() {
 
 bool RemoveBrowsingCacheForMainTabs() {
   __block BOOL caches_cleared = NO;
-  [chrome_test_util::GetMainController()
+  [chrome_test_util::GetMainController().sceneController
       removeBrowsingDataForBrowserState:chrome_test_util::
                                             GetOriginalBrowserState()
                              timePeriod:browsing_data::TimePeriod::ALL_TIME

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

@@ -18,10 +18,22 @@ source_set("scene") {
   deps = [
     ":main",
     "//base",
+    "//ios/chrome/app:app",
+    "//ios/chrome/app/application_delegate:application_delegate_internal",
+    "//ios/chrome/browser/browser_state",
+    "//ios/chrome/browser/browsing_data",
+    "//ios/chrome/browser/browsing_data",
+    "//ios/chrome/browser/snapshots",
     "//ios/chrome/browser/tabs:tabs",
+    "//ios/chrome/browser/ui/browser_view",
     "//ios/chrome/browser/ui/commands:commands",
+    "//ios/chrome/browser/ui/history",
+    "//ios/chrome/browser/ui/settings:settings_root",
+    "//ios/chrome/browser/ui/signin_interaction",
     "//ios/chrome/browser/ui/tab_grid",
     "//ios/chrome/browser/ui/util:multiwindow_util",
+    "//ios/chrome/browser/url_loading",
+    "//ios/chrome/browser/web_state_list",
   ]
 
   libs = [ "UIKit.framework" ]

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

@@ -7,10 +7,13 @@
 
 #import <UIKit/UIKit.h>
 
+#import "ios/chrome/browser/ui/commands/application_commands.h"
 #import "ios/chrome/browser/ui/main/scene_state.h"
 
+@protocol MainControllerGuts;
+
 // The controller object for a scene. Reacts to scene state changes.
-@interface SceneController : NSObject <SceneStateObserver>
+@interface SceneController : NSObject <SceneStateObserver, ApplicationCommands>
 
 - (instancetype)init NS_UNAVAILABLE;
 - (instancetype)initWithSceneState:(SceneState*)sceneState
@@ -19,6 +22,13 @@
 // The state of the scene controlled by this object.
 @property(nonatomic, weak, readonly) SceneState* sceneState;
 
+// Returns whether the scene is showing or partially showing the
+// incognito panel.
+@property(nonatomic, assign, readonly) BOOL incognitoContentVisible;
+
+// A temporary pointer to MainController.
+@property(nonatomic, weak) id<MainControllerGuts> mainController;
+
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_MAIN_SCENE_CONTROLLER_H_

ios/chrome/browser/ui/signin_interaction/signin_interaction_controller_egtest.mm

@@ -79,7 +79,7 @@ void TapOnPrimarySignInButtonInRecentTabs() {
 // Removes all browsing data.
 void RemoveBrowsingData() {
   __block BOOL browsing_data_removed = NO;
-  [chrome_test_util::GetMainController()
+  [chrome_test_util::GetMainController().sceneController
       removeBrowsingDataForBrowserState:chrome_test_util::
                                             GetOriginalBrowserState()
                              timePeriod:browsing_data::TimePeriod::ALL_TIME

ios/chrome/test/app/browsing_data_test_util.mm

@@ -32,7 +32,7 @@ bool ClearBrowsingData(bool off_the_record, BrowsingDataRemoveMask mask) {
                      : chrome_test_util::GetOriginalBrowserState();
 
   __block bool did_complete = false;
-  [chrome_test_util::GetMainController()
+  [chrome_test_util::GetMainController().sceneController
       removeBrowsingDataForBrowserState:browser_state
                              timePeriod:browsing_data::TimePeriod::ALL_TIME
                              removeMask:mask