Cleanup legacyImplementation code from FlatList

Summary:
This functionality was removed here: facebook@636d01b

This is just a step of cleanup

Reviewed By: yungsters

Differential Revision: D10515512

fbshipit-source-id: 6d24cc9c53c71924a82c67a4058585ee978de2d9

Author: elicwhite

Libraries/Lists/FlatList.js

@@ -10,11 +10,9 @@
 'use strict';
 
 const deepDiffer = require('deepDiffer');
-const MetroListView = require('MetroListView'); // Used as a fallback legacy option
 const React = require('React');
 const View = require('View');
 const VirtualizedList = require('VirtualizedList');
-const ListView = require('ListView');
 const StyleSheet = require('StyleSheet');
 
 const invariant = require('fbjs/lib/invariant');
@@ -359,7 +357,6 @@ class FlatList<ItemT> extends React.PureComponent<Props<ItemT>, void> {
     viewPosition?: number,
   }) {
     if (this._listRef) {
-      // $FlowFixMe Found when typing ListView
       this._listRef.scrollToIndex(params);
     }
   }
@@ -376,7 +373,6 @@ class FlatList<ItemT> extends React.PureComponent<Props<ItemT>, void> {
     viewPosition?: number,
   }) {
     if (this._listRef) {
-      // $FlowFixMe Found when typing ListView
       this._listRef.scrollToItem(params);
     }
   }
@@ -388,7 +384,6 @@ class FlatList<ItemT> extends React.PureComponent<Props<ItemT>, void> {
    */
   scrollToOffset(params: {animated?: ?boolean, offset: number}) {
     if (this._listRef) {
-      // $FlowFixMe Found when typing ListView
       this._listRef.scrollToOffset(params);
     }
   }
@@ -400,7 +395,6 @@ class FlatList<ItemT> extends React.PureComponent<Props<ItemT>, void> {
    */
   recordInteraction() {
     if (this._listRef) {
-      // $FlowFixMe Found when typing ListView
       this._listRef.recordInteraction();
     }
   }
@@ -412,7 +406,6 @@ class FlatList<ItemT> extends React.PureComponent<Props<ItemT>, void> {
    */
   flashScrollIndicators() {
     if (this._listRef) {
-      // $FlowFixMe Found when typing ListView
       this._listRef.flashScrollIndicators();
     }
   }
@@ -422,14 +415,12 @@ class FlatList<ItemT> extends React.PureComponent<Props<ItemT>, void> {
    */
   getScrollResponder() {
     if (this._listRef) {
-      // $FlowFixMe Found when typing ListView
       return this._listRef.getScrollResponder();
     }
   }
 
   getScrollableNode() {
     if (this._listRef) {
-      // $FlowFixMe Found when typing ListView
       return this._listRef.getScrollableNode();
     }
   }
@@ -488,8 +479,7 @@ class FlatList<ItemT> extends React.PureComponent<Props<ItemT>, void> {
     this._checkProps(this.props);
   }
 
-  _hasWarnedLegacy = false;
-  _listRef: null | VirtualizedList | ListView | MetroListView;
+  _listRef: ?React.ElementRef<typeof VirtualizedList>;
   _virtualizedListPairs: Array<ViewabilityConfigCallbackPair> = [];
 
   _captureRef = ref => {
@@ -501,7 +491,6 @@ class FlatList<ItemT> extends React.PureComponent<Props<ItemT>, void> {
       getItem,
       getItemCount,
       horizontal,
-      legacyImplementation,
       numColumns,
       columnWrapperStyle,
       onViewableItemsChanged,
@@ -519,22 +508,6 @@ class FlatList<ItemT> extends React.PureComponent<Props<ItemT>, void> {
         'columnWrapperStyle not supported for single column lists',
       );
     }
-    if (legacyImplementation) {
-      invariant(
-        numColumns === 1,
-        'Legacy list does not support multiple columns.',
-      );
-      // Warning: may not have full feature parity and is meant more for debugging and performance
-      // comparison.
-      if (!this._hasWarnedLegacy) {
-        console.warn(
-          'FlatList: legacyImplementation is deprecated and will be removed in a ' +
-            'future release - some features not supported and performance may suffer. ' +
-            'Please migrate to the default implementation.',
-        );
-        this._hasWarnedLegacy = true;
-      }
-    }
     invariant(
       !(onViewableItemsChanged && viewabilityConfigCallbackPairs),
       'FlatList does not support setting both onViewableItemsChanged and ' +
@@ -648,27 +621,17 @@ class FlatList<ItemT> extends React.PureComponent<Props<ItemT>, void> {
   };
 
   render() {
-    if (this.props.legacyImplementation) {
-      return (
-        <MetroListView
-          {...this.props}
-          items={this.props.data}
-          ref={this._captureRef}
-        />
-      );
-    } else {
-      return (
-        <VirtualizedList
-          {...this.props}
-          renderItem={this._renderItem}
-          getItem={this._getItem}
-          getItemCount={this._getItemCount}
-          keyExtractor={this._keyExtractor}
-          ref={this._captureRef}
-          viewabilityConfigCallbackPairs={this._virtualizedListPairs}
-        />
-      );
-    }
+    return (
+      <VirtualizedList
+        {...this.props}
+        renderItem={this._renderItem}
+        getItem={this._getItem}
+        getItemCount={this._getItemCount}
+        keyExtractor={this._keyExtractor}
+        ref={this._captureRef}
+        viewabilityConfigCallbackPairs={this._virtualizedListPairs}
+      />
+    );
   }
 }