[video_player] Made the video_player clean up after itself on iOS. (#2528)

diff --git a/packages/video_player/video_player/CHANGELOG.md b/packages/video_player/video_player/CHANGELOG.md
index bff37f5..c74aa31 100644
--- a/packages/video_player/video_player/CHANGELOG.md
+++ b/packages/video_player/video_player/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 0.10.8
+
+* Added support for cleaning up the plugin if used for add-to-app (Flutter
+  v1.15.3 is required for that feature).
+
 ## 0.10.7
 
 * `VideoPlayerController` support for reading closed caption files. 

diff --git a/packages/video_player/video_player/ios/Classes/FLTVideoPlayerPlugin.m b/packages/video_player/video_player/ios/Classes/FLTVideoPlayerPlugin.m
index 0d3a29e..39313fa 100644
--- a/packages/video_player/video_player/ios/Classes/FLTVideoPlayerPlugin.m
+++ b/packages/video_player/video_player/ios/Classes/FLTVideoPlayerPlugin.m

@@ -6,6 +6,10 @@
 #import <AVFoundation/AVFoundation.h>
 #import <GLKit/GLKit.h>
 
+#if !__has_feature(objc_arc)
+#error Code Requires ARC.
+#endif
+
 int64_t FLTCMTimeToMillis(CMTime time) {
   if (time.timescale == 0) return 0;
   return time.value * 1000 / time.timescale;
@@ -13,7 +17,7 @@
 
 @interface FLTFrameUpdater : NSObject
 @property(nonatomic) int64_t textureId;
-@property(nonatomic, readonly) NSObject<FlutterTextureRegistry>* registry;
+@property(nonatomic, weak, readonly) NSObject<FlutterTextureRegistry>* registry;
 - (void)onDisplayLink:(CADisplayLink*)link;
 @end
 
@@ -386,7 +390,10 @@
   return nil;
 }
 
-- (void)dispose {
+/// This method allows you to dispose without touching the event channel.  This
+/// is useful for the case where the Engine is in the process of deconstruction
+/// so the channel is going to die or is already dead.
+- (void)disposeSansEventChannel {
   _disposed = true;
   [_displayLink invalidate];
   [[_player currentItem] removeObserver:self forKeyPath:@"status" context:statusContext];
@@ -404,17 +411,20 @@
                                 context:playbackBufferFullContext];
   [_player replaceCurrentItemWithPlayerItem:nil];
   [[NSNotificationCenter defaultCenter] removeObserver:self];
+}
+
+- (void)dispose {
+  [self disposeSansEventChannel];
   [_eventChannel setStreamHandler:nil];
 }
 
 @end
 
 @interface FLTVideoPlayerPlugin ()
-@property(readonly, nonatomic) NSObject<FlutterTextureRegistry>* registry;
-@property(readonly, nonatomic) NSObject<FlutterBinaryMessenger>* messenger;
-@property(readonly, nonatomic) NSMutableDictionary* players;
-@property(readonly, nonatomic) NSObject<FlutterPluginRegistrar>* registrar;
-
+@property(readonly, weak, nonatomic) NSObject<FlutterTextureRegistry>* registry;
+@property(readonly, weak, nonatomic) NSObject<FlutterBinaryMessenger>* messenger;
+@property(readonly, strong, nonatomic) NSMutableDictionary* players;
+@property(readonly, strong, nonatomic) NSObject<FlutterPluginRegistrar>* registrar;
 @end
 
 @implementation FLTVideoPlayerPlugin
@@ -424,6 +434,7 @@
                                   binaryMessenger:[registrar messenger]];
   FLTVideoPlayerPlugin* instance = [[FLTVideoPlayerPlugin alloc] initWithRegistrar:registrar];
   [registrar addMethodCallDelegate:instance channel:channel];
+  [registrar publish:instance];
 }
 
 - (instancetype)initWithRegistrar:(NSObject<FlutterPluginRegistrar>*)registrar {
@@ -436,6 +447,14 @@
   return self;
 }
 
+- (void)detachFromEngineForRegistrar:(NSObject<FlutterPluginRegistrar>*)registrar {
+  for (NSNumber* textureId in _players.allKeys) {
+    FLTVideoPlayer* player = _players[textureId];
+    [player disposeSansEventChannel];
+  }
+  [_players removeAllObjects];
+}
+
 - (void)onPlayerSetup:(FLTVideoPlayer*)player
          frameUpdater:(FLTFrameUpdater*)frameUpdater
                result:(FlutterResult)result {
@@ -485,7 +504,6 @@
     } else {
       result(FlutterMethodNotImplemented);
     }
-
   } else {
     NSDictionary* argsMap = call.arguments;
     int64_t textureId = ((NSNumber*)argsMap[@"textureId"]).unsignedIntegerValue;

diff --git a/packages/video_player/video_player/pubspec.yaml b/packages/video_player/video_player/pubspec.yaml
index 43a69a5..417d21f 100644
--- a/packages/video_player/video_player/pubspec.yaml
+++ b/packages/video_player/video_player/pubspec.yaml

@@ -1,7 +1,7 @@
 name: video_player
 description: Flutter plugin for displaying inline video with other Flutter
   widgets on Android and iOS.
-version: 0.10.7
+version: 0.10.8
 homepage: https://github.com/flutter/plugins/tree/master/packages/video_player/video_player
 
 flutter: