[multiball] Remove sceneShowingBlockingUI property.

This property was replaced with the UI blocker abstracted in a protocol
in crrev/2288853 but it was still used in a few places, thus that CL
introduced bugs, including potentially showing sign in promo when the
blocking UI is shown, and switch-to-open-window button never working.

Remove this property and replace it by extending UIBlocking* protocols.

Bug: 1103565
Change-Id: Ib79d2968c1fe545ef5cd87cc196802ad6097345c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2398684Reviewed-by: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#805270}

ios/chrome/app/application_delegate/app_state.h

@@ -64,11 +64,6 @@ initWithBrowserLauncher:(id<BrowserLauncher>)browserLauncher
 // by the app delegate.
 @property(nonatomic, strong) SceneState* mainSceneState;
 
-// When a modal UI (that requires user to interact with it before any further
-// interaction with the app is allowed) is shown, this tracks the scene where it
-// is shown. When there is no blocking UI shown in any scene, this is nil.
-@property(nonatomic, weak, readonly) SceneState* sceneShowingBlockingUI;
-
 // Indicates that this app launch is one after a crash.
 @property(nonatomic, assign) BOOL postCrashLaunch;
 

ios/chrome/app/application_delegate/app_state.mm

@@ -698,6 +698,10 @@ initWithBrowserLauncher:(id<BrowserLauncher>)browserLauncher
   }
 }
 
+- (id<UIBlockerTarget>)currentUIBlocker {
+  return self.uiBlockerTarget;
+}
+
 #pragma mark - Scene notifications
 
 // Handler for UISceneDidActivateNotification.

ios/chrome/app/main_controller.mm

@@ -1239,24 +1239,12 @@ void MainControllerAuthenticationServiceDelegate::ClearBrowsingData(
 
 - (void)activateBlockingScene:(UIScene*)requestingScene
     API_AVAILABLE(ios(13.0)) {
-  if (@available(iOS 13, *)) {
-    UISceneActivationRequestOptions* options =
-        [[UISceneActivationRequestOptions alloc] init];
-    options.requestingScene = requestingScene;
-    UIScene* blockingScene = self.appState.sceneShowingBlockingUI.scene;
-    if (!blockingScene) {
-      return;
-    }
-    [[UIApplication sharedApplication]
-        requestSceneSessionActivation:blockingScene.session
-                         userActivity:nil
-                              options:options
-                         errorHandler:^(NSError* error) {
-                           LOG(ERROR) << base::SysNSStringToUTF8(
-                               error.localizedDescription);
-                           NOTREACHED();
-                         }];
+  id<UIBlockerTarget> uiBlocker = self.appState.currentUIBlocker;
+  if (!uiBlocker) {
+    return;
   }
+
+  [uiBlocker bringBlockerToFront:requestingScene];
 }
 
 @end

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

@@ -769,7 +769,7 @@ const char kMultiWindowOpenInNewWindowHistogram[] =
     }
   }
   // Don't show the promo if there is a blocking task in process.
-  if (self.sceneState.appState.sceneShowingBlockingUI)
+  if (self.sceneState.appState.currentUIBlocker)
     return NO;
   // Don't show the promo in Incognito mode.
   if (self.currentInterface == self.incognitoInterface)

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

@@ -5,6 +5,9 @@
 #import "ios/chrome/browser/ui/main/scene_state.h"
 
 #import "base/ios/crb_protocol_observers.h"
+#include "base/logging.h"
+#include "base/notreached.h"
+#include "base/strings/sys_string_conversions.h"
 #import "ios/chrome/app/application_delegate/app_state.h"
 #import "ios/chrome/app/chrome_overlay_window.h"
 #import "ios/chrome/browser/ui/main/scene_controller.h"
@@ -128,10 +131,33 @@
   [self.observers sceneState:self receivedUserActivity:pendingUserActivity];
 }
 
+#pragma mark - UIBlockerTarget
+
 - (id<UIBlockerManager>)uiBlockerManager {
   return _appState;
 }
 
+- (void)bringBlockerToFront:(UIScene*)requestingScene API_AVAILABLE(ios(13)) {
+  if (!IsMultipleScenesSupported()) {
+    return;
+  }
+  if (@available(iOS 13, *)) {
+    UISceneActivationRequestOptions* options =
+        [[UISceneActivationRequestOptions alloc] init];
+    options.requestingScene = requestingScene;
+
+    [[UIApplication sharedApplication]
+        requestSceneSessionActivation:self.scene.session
+                         userActivity:nil
+                              options:options
+                         errorHandler:^(NSError* error) {
+                           LOG(ERROR) << base::SysNSStringToUTF8(
+                               error.localizedDescription);
+                           NOTREACHED();
+                         }];
+  }
+}
+
 #pragma mark - debug
 
 - (NSString*)description {

ios/chrome/browser/ui/scoped_ui_blocker/ui_blocker_manager.h

@@ -12,6 +12,9 @@
 // Manager in charge to block and unblock all UI.
 @protocol UIBlockerManager <NSObject>
 
+// The current UI blocker, if any.
+- (id<UIBlockerTarget>)currentUIBlocker;
+
 // Call this when showing a new blocking UI in |target|.
 // It is an error to call this for target A when target B is already showing one
 // or more blocking UI.

ios/chrome/browser/ui/scoped_ui_blocker/ui_blocker_target.h

@@ -8,6 +8,7 @@
 #import <Foundation/Foundation.h>
 
 @protocol UIBlockerManager;
+@class UIScene;
 
 // Target to block all UI.
 @protocol UIBlockerTarget <NSObject>
@@ -15,6 +16,10 @@
 // Returns UI blocker manager.
 @property(nonatomic, weak, readonly) id<UIBlockerManager> uiBlockerManager;
 
+// Force the blocking UI to appear. Specifically, bring the blocking UI window
+// forward.
+- (void)bringBlockerToFront:(UIScene*)requestingScene API_AVAILABLE(ios(13));
+
 @end
 
 #endif  // IOS_CHROME_BROWSER_UI_SCOPED_UI_BLOCKER_UI_BLOCKER_TARGET_H_