fixed bugs in ios version

ios/Flutter/Flutter.framework/Headers/FlutterPlugin.h

@@ -10,6 +10,7 @@
 #include "FlutterBinaryMessenger.h"
 #include "FlutterChannels.h"
 #include "FlutterCodecs.h"
+#include "FlutterTexture.h"
 
 NS_ASSUME_NONNULL_BEGIN
 @protocol FlutterPluginRegistrar;
@@ -142,6 +143,14 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (NSObject<FlutterBinaryMessenger>*)messenger;
 
+/**
+ Returns a `FlutterTextureRegistry` for registering textures
+ provided by the plugin.
+
+ - Returns: The texture registry.
+ */
+- (NSObject<FlutterTextureRegistry>*)textures;
+
 /**
  Publishes a value for external use of the plugin.