remove mixin on Libraries/Components/ScrollResponder.js (#21589)

Summary:
Related to #21485.
Removed Subscribable.Mixin from the Libraries/Components/ScrollResponder.js

 - [x] npm run prettier
 - [x] npm run flow-check-ios
 - [x] npm run flow-check-android

[GENERAL] [ENHANCEMENT] [Libraries/Components/ScrollResponder.js] - remove Subscribable.Mixin dependency
Pull Request resolved: #21589

Differential Revision: D10275517

Pulled By: RSNara

fbshipit-source-id: 28af7f0944e978609a1b3be05b8a51557e67bc1b

Libraries/Components/ScrollResponder.js

@@ -14,7 +14,6 @@ const Dimensions = require('Dimensions');
 const FrameRateLogger = require('FrameRateLogger');
 const Keyboard = require('Keyboard');
 const ReactNative = require('ReactNative');
-const Subscribable = require('Subscribable');
 const TextInputState = require('TextInputState');
 const UIManager = require('UIManager');
 
@@ -25,6 +24,8 @@ const warning = require('fbjs/lib/warning');
 
 const {ScrollViewManager} = require('NativeModules');
 
+import type EmitterSubscription from 'EmitterSubscription';
+
 /**
  * Mixin that can be integrated in order to handle scrolling that plays well
  * with `ResponderEventPlugin`. Integrate with your platform specific scroll
@@ -115,7 +116,10 @@ type State = {
 type Event = Object;
 
 const ScrollResponderMixin = {
-  mixins: [Subscribable.Mixin],
+  _subscriptionKeyboardWillShow: (null: ?EmitterSubscription),
+  _subscriptionKeyboardWillHide: (null: ?EmitterSubscription),
+  _subscriptionKeyboardDidShow: (null: ?EmitterSubscription),
+  _subscriptionKeyboardDidHide: (null: ?EmitterSubscription),
   scrollResponderMixinGetInitialState: function(): State {
     return {
       isTouching: false,
@@ -602,28 +606,39 @@ const ScrollResponderMixin = {
 
     this.keyboardWillOpenTo = null;
     this.additionalScrollOffset = 0;
-    this.addListenerOn(
-      Keyboard,
+    this._subscriptionKeyboardWillShow = Keyboard.addListener(
       'keyboardWillShow',
       this.scrollResponderKeyboardWillShow,
     );
-    this.addListenerOn(
-      Keyboard,
+    this._subscriptionKeyboardWillHide = Keyboard.addListener(
       'keyboardWillHide',
       this.scrollResponderKeyboardWillHide,
     );
-    this.addListenerOn(
-      Keyboard,
+    this._subscriptionKeyboardDidShow = Keyboard.addListener(
       'keyboardDidShow',
       this.scrollResponderKeyboardDidShow,
     );
-    this.addListenerOn(
-      Keyboard,
+    this._subscriptionKeyboardDidHide = Keyboard.addListener(
       'keyboardDidHide',
       this.scrollResponderKeyboardDidHide,
     );
   },
 
+  componentWillUnmount: function() {
+    if (this._subscriptionKeyboardWillShow != null) {
+      this._subscriptionKeyboardWillShow.remove();
+    }
+    if (this._subscriptionKeyboardWillHide != null) {
+      this._subscriptionKeyboardWillHide.remove();
+    }
+    if (this._subscriptionKeyboardDidShow != null) {
+      this._subscriptionKeyboardDidShow.remove();
+    }
+    if (this._subscriptionKeyboardDidHide != null) {
+      this._subscriptionKeyboardDidHide.remove();
+    }
+  },
+
   /**
    * Warning, this may be called several times for a single keyboard opening.
    * It's best to store the information in this method and then take any action