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/826024Reviewed-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}

ios/chrome/app/main_controller.mm

@@ -2066,7 +2066,6 @@ const int kExternalFilesCleanupDelaySeconds = 60;
 - (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

@@ -92,7 +92,6 @@ const int64_t kAuthenticationFlowTimeoutSeconds = 10;
   [_alertCoordinator executeCancelHandler];
   [_alertCoordinator stop];
   if (_navigationController) {
-    [_navigationController settingsWillBeDismissed];
     _navigationController = nil;
     [[_delegate presentingViewController] dismissViewControllerAnimated:NO
                                                              completion:nil];
@@ -409,7 +408,6 @@ const int64_t kAuthenticationFlowTimeoutSeconds = 10;
     strongSelf->_navigationController = nil;
     [[strongSelf delegate] didChooseClearDataPolicy:shouldClearData];
   };
-  [_navigationController settingsWillBeDismissed];
   [[_delegate presentingViewController] dismissViewControllerAnimated:YES
                                                            completion:block];
 }
@@ -427,7 +425,6 @@ 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

@@ -41,7 +41,8 @@ class ChromeBrowserState;
 
 // Controller to modify user settings.
 @interface SettingsNavigationController
-    : UINavigationController<ApplicationSettingsCommands>
+    : UINavigationController<ApplicationSettingsCommands,
+                             SettingsControllerProtocol>
 
 // Whether sync changes should be committed when the settings are being
 // dismissed. Defaults to YES.
@@ -138,10 +139,6 @@ 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

@@ -312,6 +312,13 @@ 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]) {