cherrypick: 最后一个flutter页面关闭的时候回调对Engine的OwnerViewController清空

ios/Classes/Boost/FLBFlutterApplicationInterface.h

@@ -75,6 +75,9 @@ NS_ASSUME_NONNULL_BEGIN
                           params:(NSDictionary *)params
                         uniqueId:(NSString *)uniqueId;
 
+- (void)onShownContainerChanged:(NSString *)uniqueId
+                         params:(NSDictionary *)params;
+
 @end
 NS_ASSUME_NONNULL_END
 

ios/Classes/Boost/FlutterBoostPlugin.m

@@ -67,8 +67,15 @@
                                                         result(@(r));
                                                     }];
     }else if([@"onShownContainerChanged" isEqualToString:call.method]){
-        NSString *newName = call.arguments[@"newName"];
+        NSDictionary *args = [FLBCollectionHelper deepCopyNSDictionary:call.arguments
+        filter:^bool(id  _Nonnull value) {
+            return ![value isKindOfClass:NSNull.class];
+        }];
+        
+        NSString *newName = args[@"newName"];
+        NSString *uid = args[@"uniqueId"];
         if(newName){
+            [[FlutterBoostPlugin2 sharedInstance].application onShownContainerChanged:uid params:args];
             [NSNotificationCenter.defaultCenter postNotificationName:@"flutter_boost_container_showed"
                                                               object:newName];
         }

ios/Classes/Engine/FLBFlutterApplication.m

@@ -226,4 +226,13 @@
     }
 }
 
+- (void)onShownContainerChanged:(NSString *)uniqueId
+                         params:(NSDictionary *)params{
+    NSString *oldName = params[@"oldName"];
+    NSString *newName = params[@"newName"];
+    if (oldName!=nil && [newName isEqualToString:@"default"]) {
+        [self.flutterProvider detach];
+    }
+}
+
 @end

ios/Classes/container/FLBFlutterViewContainer.m

@@ -268,7 +268,6 @@ static NSUInteger kInstanceCounter = 0;
     //     [self surfaceUpdated:NO];
     // }
     [super bridge_viewDidDisappear:animated];
-    [FLUTTER_APP resume];
 }
 
 - (void)installSplashScreenViewIfNecessary {