co-existence with cordova-plugin-local-notification on iOS

Local notifications on iOS via cordova-plugin-local-notification are working again.
Click-callback for remote notifications not working right now.

Details:
UNUserNotificationCenter accepts a single delegate that handles the display of notifications. cordova-plugin-firebase now stores a reference to the existing delegate if any and proxies the delegate-calls (cordova-plugin-local-notification is already doing that in the other direction when applicable).

src/ios/AppDelegate+FirebasePlugin.m

@@ -14,9 +14,22 @@ @interface AppDelegate () <UNUserNotificationCenterDelegate, FIRMessagingDelegat
 #endif
 
 #define kApplicationInBackgroundKey @"applicationInBackground"
+#define kDelegateKey @"delegate"
 
 @implementation AppDelegate (FirebasePlugin)
 
+#if defined(__IPHONE_10_0) && __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_10_0
+
+- (void)setDelegate:(id)delegate {
+    objc_setAssociatedObject(self, kDelegateKey, delegate, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
+}
+
+- (id)delegate {
+    return objc_getAssociatedObject(self, kDelegateKey);
+}
+
+#endif
+
 + (void)load {
     Method original = class_getInstanceMethod(self, @selector(application:didFinishLaunchingWithOptions:));
     Method swizzled = class_getInstanceMethod(self, @selector(application:swizzledDidFinishLaunchingWithOptions:));
@@ -41,6 +54,10 @@ - (BOOL)application:(UIApplication *)application swizzledDidFinishLaunchingWithO
     // [START set_messaging_delegate]
     [FIRMessaging messaging].delegate = self;
     // [END set_messaging_delegate]
+#if defined(__IPHONE_10_0) && __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_10_0
+    self.delegate = [UNUserNotificationCenter currentNotificationCenter].delegate;
+    [UNUserNotificationCenter currentNotificationCenter].delegate = self;
+#endif
 
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(tokenRefreshNotification:)
                                                  name:kFIRInstanceIDTokenRefreshNotification object:nil];
@@ -120,6 +137,15 @@ - (void)messaging:(FIRMessaging *)messaging didReceiveMessage:(FIRMessagingRemot
 - (void)userNotificationCenter:(UNUserNotificationCenter *)center
        willPresentNotification:(UNNotification *)notification
          withCompletionHandler:(void (^)(UNNotificationPresentationOptions))completionHandler {
+
+    [self.delegate userNotificationCenter:center
+              willPresentNotification:notification
+                withCompletionHandler:completionHandler];
+
+    UNNotificationRequest* toast = notification.request;
+    if (![toast.trigger isKindOfClass:UNPushNotificationTrigger.class])
+        return;
+
     NSDictionary *mutableUserInfo = [notification.request.content.userInfo mutableCopy];
 
     [mutableUserInfo setValue:self.applicationInBackground forKey:@"tap"];
@@ -130,6 +156,15 @@ - (void)userNotificationCenter:(UNUserNotificationCenter *)center
     [FirebasePlugin.firebasePlugin sendNotification:mutableUserInfo];
 }
 
+- (void) userNotificationCenter:(UNUserNotificationCenter *)center
+ didReceiveNotificationResponse:(UNNotificationResponse *)response
+          withCompletionHandler:(void (^)(void))completionHandler
+{
+    [self.delegate userNotificationCenter:center
+       didReceiveNotificationResponse:response
+                withCompletionHandler:completionHandler];
+}
+
 // Receive data message on iOS 10 devices.
 - (void)applicationReceivedRemoteMessage:(FIRMessagingRemoteMessage *)remoteMessage {
     // Print full message

src/ios/FirebasePlugin.m

@@ -119,15 +119,13 @@ - (void)grantPermission:(CDVInvokedUrlCommand *)command {
 
             if (![NSThread isMainThread]) {
                 dispatch_sync(dispatch_get_main_queue(), ^{
-                    [[UNUserNotificationCenter currentNotificationCenter] setDelegate:self];
                     [[FIRMessaging messaging] setDelegate:self];
                     [[UIApplication sharedApplication] registerForRemoteNotifications];
 
                     CDVPluginResult *pluginResult = [CDVPluginResult resultWithStatus: granted ? CDVCommandStatus_OK : CDVCommandStatus_ERROR];
                     [self.commandDelegate sendPluginResult:pluginResult callbackId:command.callbackId];
                 });
             } else {
-                [[UNUserNotificationCenter currentNotificationCenter] setDelegate:self];
                 [[FIRMessaging messaging] setDelegate:self];
                 [[UIApplication sharedApplication] registerForRemoteNotifications];
                 CDVPluginResult *pluginResult = [CDVPluginResult resultWithStatus:CDVCommandStatus_OK];