Add commodity methods on OperationQueue and use them in key backup setup view models.

Riot/Modules/KeyBackup/Setup/Passphrase/KeyBackupSetupPassphraseViewModel.swift

@@ -60,11 +60,7 @@ final class KeyBackupSetupPassphraseViewModel: KeyBackupSetupPassphraseViewModel
     init(keyBackup: MXKeyBackup) {
         self.passwordStrengthManager = PasswordStrengthManager()
         self.keyBackup = keyBackup
-        
-        let coordinatorDelegateQueue = OperationQueue()
-        coordinatorDelegateQueue.name = "KeyBackupSetupPassphraseViewModel.coordinatorDelegateQueue"
-        coordinatorDelegateQueue.maxConcurrentOperationCount = 1
-        self.coordinatorDelegateQueue = coordinatorDelegateQueue
+        self.coordinatorDelegateQueue = OperationQueue.vc_createSerialOperationQueue(name: "\(type(of: self)).coordinatorDelegateQueue")
     }
     
     // MARK: - Public
@@ -74,12 +70,12 @@ final class KeyBackupSetupPassphraseViewModel: KeyBackupSetupPassphraseViewModel
         case .setupPassphrase:
             self.setupPassphrase()
         case .skip:
-            self.pauseCoordinatorOperations()
+            self.coordinatorDelegateQueue.vc_pause()
             self.viewDelegate?.keyBackupSetupPassphraseViewModelShowSkipAlert(self)
-        case.skipAlertContinue:
-            self.resumeCoordinatorOperations()
+        case.skipAlertContinue:            
+            self.coordinatorDelegateQueue.vc_resume()
         case.skipAlertSkip:
-            self.cancelCoordinatorOperations()
+            self.coordinatorDelegateQueue.cancelAllOperations()
             self.coordinatorDelegate?.keyBackupSetupPassphraseViewModelDidCancel(self)
         }
     }
@@ -123,16 +119,4 @@ final class KeyBackupSetupPassphraseViewModel: KeyBackupSetupPassphraseViewModel
         }
         return self.passwordStrengthManager.passwordStrength(for: password)
     }
-    
-    private func pauseCoordinatorOperations() {
-        self.coordinatorDelegateQueue.isSuspended = true
-    }
-    
-    private func resumeCoordinatorOperations() {
-        self.coordinatorDelegateQueue.isSuspended = false
-    }
-    
-    private func cancelCoordinatorOperations() {
-        self.coordinatorDelegateQueue.cancelAllOperations()
-    }
 }