Rework "cancel navigate back" logic.

// FREEBIE

Signal/src/ViewControllers/NewGroupViewController.m

@@ -50,7 +50,6 @@ const NSUInteger kNewGroupViewControllerAvatarWidth = 68;
 @property (nonatomic) NSMutableSet<NSString *> *memberRecipientIds;
 
 @property (nonatomic) BOOL hasUnsavedChanges;
-@property (nonatomic) BOOL shouldIgnoreSavedChanges;
 @property (nonatomic) BOOL hasAppeared;
 
 @end
@@ -552,7 +551,7 @@ const NSUInteger kNewGroupViewControllerAvatarWidth = 68;
 {
     [self.groupNameTextField resignFirstResponder];
 
-    if (!self.hasUnsavedChanges || self.shouldIgnoreSavedChanges) {
+    if (!self.hasUnsavedChanges) {
         // If user made no changes, return to conversation settings view.
         [self.navigationController popViewControllerAnimated:YES];
         return;
@@ -571,7 +570,6 @@ const NSUInteger kNewGroupViewControllerAvatarWidth = 68;
                                                      @"The label for the 'discard' button in alerts and action sheets.")
                                            style:UIAlertActionStyleDestructive
                                          handler:^(UIAlertAction *action) {
-                                             self.shouldIgnoreSavedChanges = YES;
                                              [self.navigationController popViewControllerAnimated:YES];
                                          }]];
     [controller addAction:[UIAlertAction actionWithTitle:NSLocalizedString(@"TXT_CANCEL_TITLE", nil)
@@ -655,8 +653,8 @@ const NSUInteger kNewGroupViewControllerAvatarWidth = 68;
 
 - (BOOL)shouldCancelNavigationBack
 {
-    BOOL result = self.hasUnsavedChanges && !self.shouldIgnoreSavedChanges;
-    if (result) {
+    BOOL result = self.hasUnsavedChanges;
+    if (self.hasUnsavedChanges) {
         [self backButtonPressed];
     }
     return result;

Signal/src/ViewControllers/OWSNavigationController.h

@@ -8,6 +8,8 @@
 // presses and back gestures should implement this protocol.
 @protocol OWSNavigationView <NSObject>
 
+// shouldCancelNavigationBack will be called if the back button was pressed or
+// if a back gesture was performed but not if the view is popped programmatically.
 - (BOOL)shouldCancelNavigationBack;
 
 @end

Signal/src/ViewControllers/OWSNavigationController.m

@@ -37,6 +37,8 @@
     OWSAssert(self.interactivePopGestureRecognizer.delegate == self);
     UIViewController *topViewController = self.topViewController;
 
+    // wasBackButtonClicked is YES if the back button was pressed but not
+    // if a back gesture was performed or if the view is popped programmatically.
     BOOL wasBackButtonClicked = topViewController.navigationItem == item;
     BOOL result = YES;
     if (wasBackButtonClicked) {

Signal/src/ViewControllers/ProfileViewController.m

@@ -44,8 +44,6 @@ NSString *const kProfileView_LastPresentedDate = @"kProfileView_LastPresentedDat
 
 @property (nonatomic) BOOL hasUnsavedChanges;
 
-@property (nonatomic) BOOL shouldIgnoreSavedChanges;
-
 @property (nonatomic) ProfileViewMode profileViewMode;
 
 @property (nonatomic) YapDatabaseConnection *databaseConnection;
@@ -209,7 +207,7 @@ NSString *const kProfileView_LastPresentedDate = @"kProfileView_LastPresentedDat
 {
     [self.nameTextField resignFirstResponder];
 
-    if (!self.hasUnsavedChanges || self.shouldIgnoreSavedChanges) {
+    if (!self.hasUnsavedChanges) {
         // If user made no changes, return to conversation settings view.
         [self profileCompletedOrSkipped];
         return;
@@ -228,7 +226,6 @@ NSString *const kProfileView_LastPresentedDate = @"kProfileView_LastPresentedDat
                                                      @"The label for the 'discard' button in alerts and action sheets.")
                                            style:UIAlertActionStyleDestructive
                                          handler:^(UIAlertAction *action) {
-                                             self.shouldIgnoreSavedChanges = YES;
                                              [self profileCompletedOrSkipped];
                                          }]];
     [controller addAction:[UIAlertAction actionWithTitle:NSLocalizedString(@"TXT_CANCEL_TITLE", nil)
@@ -500,7 +497,7 @@ NSString *const kProfileView_LastPresentedDate = @"kProfileView_LastPresentedDat
 
 - (BOOL)shouldCancelNavigationBack
 {
-    BOOL result = self.hasUnsavedChanges && !self.shouldIgnoreSavedChanges;
+    BOOL result = self.hasUnsavedChanges;
     if (result) {
         [self backOrSkipButtonPressed];
     }

Signal/src/ViewControllers/UpdateGroupViewController.m

@@ -50,7 +50,6 @@ NS_ASSUME_NONNULL_BEGIN
 @property (nonatomic) NSMutableSet<NSString *> *memberRecipientIds;
 
 @property (nonatomic) BOOL hasUnsavedChanges;
-@property (nonatomic) BOOL shouldIgnoreSavedChanges;
 
 @end
 
@@ -414,7 +413,7 @@ NS_ASSUME_NONNULL_BEGIN
 {
     [self.groupNameTextField resignFirstResponder];
 
-    if (!self.hasUnsavedChanges || self.shouldIgnoreSavedChanges) {
+    if (!self.hasUnsavedChanges) {
         // If user made no changes, return to conversation settings view.
         [self.navigationController popViewControllerAnimated:YES];
         return;
@@ -442,7 +441,6 @@ NS_ASSUME_NONNULL_BEGIN
                                                              @"The label for the 'don't save' button in action sheets.")
                                                    style:UIAlertActionStyleDestructive
                                                  handler:^(UIAlertAction *action) {
-                                                     self.shouldIgnoreSavedChanges = YES;
                                                      [self.navigationController popViewControllerAnimated:YES];
                                                  }]];
     [self presentViewController:controller animated:YES completion:nil];
@@ -534,7 +532,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 - (BOOL)shouldCancelNavigationBack
 {
-    BOOL result = self.hasUnsavedChanges && !self.shouldIgnoreSavedChanges;
+    BOOL result = self.hasUnsavedChanges;
     if (result) {
         [self backButtonPressed];
     }