Revert "Encapsulate dismissal cleanup within SettingsNavigationController"

This reverts commit 44aa3a7f.

Reason for revert: Causes crbug.com/819999

Original change's description:
> Encapsulate dismissal cleanup within SettingsNavigationController
> 
> Bug: 782943
> Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
> Change-Id: If5ebc06503448526b57f42ea6543b5373efe2c90
> Reviewed-on: https://chromium-review.googlesource.com/826024
> Reviewed-by: Mark Cogan <marq@chromium.org>
> Reviewed-by: edchin <edchin@chromium.org>
> Commit-Queue: Peter Laurens <peterlaurens@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#525372}

TBR=marq@chromium.org,edchin@chromium.org,peterlaurens@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 782943
Change-Id: If7daa3faaa515430e5354c9fe0c4654840094696
Cq-Include-Trybots: master.tryserver.chromium.mac:ios-simulator-cronet;master.tryserver.chromium.mac:ios-simulator-full-configs
Reviewed-on: https://chromium-review.googlesource.com/966961Reviewed-by: Sergio Collazos <sczs@chromium.org>
Reviewed-by: edchin <edchin@chromium.org>
Commit-Queue: Sergio Collazos <sczs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543826}

ios/chrome/app/main_controller.mm

@@ -2065,6 +2065,7 @@ void MainControllerAuthenticationServiceDelegate::ClearBrowsingData(
 - (void)closeSettingsAnimated:(BOOL)animated
                    completion:(ProceduralBlock)completion {
   DCHECK(_settingsNavigationController);
+  [_settingsNavigationController settingsWillBeDismissed];
   UIViewController* presentingViewController =
       [_settingsNavigationController presentingViewController];
   DCHECK(presentingViewController);

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

@@ -92,6 +92,7 @@ const int64_t kAuthenticationFlowTimeoutSeconds = 10;
   [_alertCoordinator executeCancelHandler];
   [_alertCoordinator stop];
   if (_navigationController) {
+    [_navigationController settingsWillBeDismissed];
     _navigationController = nil;
     [[_delegate presentingViewController] dismissViewControllerAnimated:NO
                                                              completion:nil];
@@ -414,6 +415,7 @@ const int64_t kAuthenticationFlowTimeoutSeconds = 10;
     strongSelf->_navigationController = nil;
     [[strongSelf delegate] didChooseClearDataPolicy:shouldClearData];
   };
+  [_navigationController settingsWillBeDismissed];
   [[_delegate presentingViewController] dismissViewControllerAnimated:YES
                                                            completion:block];
 }
@@ -431,6 +433,7 @@ const int64_t kAuthenticationFlowTimeoutSeconds = 10;
     strongSelf->_navigationController = nil;
     [[strongSelf delegate] didChooseCancel];
   };
+  [_navigationController settingsWillBeDismissed];
   [[_delegate presentingViewController] dismissViewControllerAnimated:YES
                                                            completion:block];
 }

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

@@ -41,8 +41,7 @@ class ChromeBrowserState;
 
 // Controller to modify user settings.
 @interface SettingsNavigationController
-    : UINavigationController<ApplicationSettingsCommands,
-                             SettingsControllerProtocol>
+    : UINavigationController<ApplicationSettingsCommands>
 
 // Whether sync changes should be committed when the settings are being
 // dismissed. Defaults to YES.
@@ -139,6 +138,10 @@ initWithRootViewController:(UIViewController*)rootViewController
 // Returns the current main browser state.
 - (ios::ChromeBrowserState*)mainBrowserState;
 
+// Notifies this |SettingsNavigationController| that it will be dismissed such
+// that it has a possibility to do necessary clean up.
+- (void)settingsWillBeDismissed;
+
 // Closes this |SettingsNavigationController| by asking its delegate.
 - (void)closeSettings;
 

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

@@ -289,13 +289,6 @@ initWithRootViewController:(UIViewController*)rootViewController
   return self;
 }
 
-- (void)viewWillDisappear:(BOOL)animated {
-  [super viewWillDisappear:animated];
-  if (self.isBeingDismissed) {
-    [self settingsWillBeDismissed];
-  }
-}
-
 - (void)settingsWillBeDismissed {
   // Notify all controllers that settings are about to be dismissed.
   for (UIViewController* controller in [self viewControllers]) {