From 2123d3a569eb0c3aba0e623ecaf17e40e317e1d3 Mon Sep 17 00:00:00 2001
From: Dan Field <dfield@gmail.com>
Date: Tue, 22 Jan 2019 15:03:25 -0800
Subject: [PATCH] Keep engine alive if VC is not deallocated (#7544)

---
 .../platform/darwin/ios/framework/Source/FlutterEngine.mm | 8 +++++---
 .../darwin/ios/framework/Source/FlutterEngine_Internal.h  | 1 +
 .../darwin/ios/framework/Source/FlutterViewController.mm  | 1 +
 3 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/shell/platform/darwin/ios/framework/Source/FlutterEngine.mm b/shell/platform/darwin/ios/framework/Source/FlutterEngine.mm
index 9daf06683083d..10491ffb0c905 100644
--- a/shell/platform/darwin/ios/framework/Source/FlutterEngine.mm
+++ b/shell/platform/darwin/ios/framework/Source/FlutterEngine.mm
@@ -144,13 +144,15 @@ - (void)setViewController:(FlutterViewController*)viewController {
   FML_DCHECK(self.iosPlatformView);
   _viewController = [viewController getWeakPtr];
   self.iosPlatformView->SetOwnerViewController(_viewController);
-  if (!viewController && !_allowHeadlessExecution) {
+  [self maybeSetupPlatformViewChannels];
+}
+
+- (void)notifyViewControllerDeallocated {
+  if (!_allowHeadlessExecution) {
     [self resetChannels];
 
     _shell.reset();
     _threadHost.Reset();
-  } else {
-    [self maybeSetupPlatformViewChannels];
   }
 }
 
diff --git a/shell/platform/darwin/ios/framework/Source/FlutterEngine_Internal.h b/shell/platform/darwin/ios/framework/Source/FlutterEngine_Internal.h
index 3627ae26e08ae..e21444cc6a9d8 100644
--- a/shell/platform/darwin/ios/framework/Source/FlutterEngine_Internal.h
+++ b/shell/platform/darwin/ios/framework/Source/FlutterEngine_Internal.h
@@ -43,6 +43,7 @@
 - (FlutterTextInputPlugin*)textInputPlugin;
 - (void)launchEngine:(NSString*)entrypoint libraryURI:(NSString*)libraryOrNil;
 - (BOOL)createShell:(NSString*)entrypoint libraryURI:(NSString*)libraryOrNil;
+- (void)notifyViewControllerDeallocated;
 
 @end
 
diff --git a/shell/platform/darwin/ios/framework/Source/FlutterViewController.mm b/shell/platform/darwin/ios/framework/Source/FlutterViewController.mm
index ca73791013b6c..8df2f3b61dbe9 100644
--- a/shell/platform/darwin/ios/framework/Source/FlutterViewController.mm
+++ b/shell/platform/darwin/ios/framework/Source/FlutterViewController.mm
@@ -430,6 +430,7 @@ - (void)viewDidDisappear:(BOOL)animated {
 }
 
 - (void)dealloc {
+  [_engine.get() notifyViewControllerDeallocated];
   [[NSNotificationCenter defaultCenter] removeObserver:self];
   [super dealloc];
 }