Revert "MM-14791 Safari and FF takes an extra frame for scroll correc…

…tion causing jump to the right post when loading more posts (mattermost#2556)" (mattermost#2560)

This reverts commit 742f772.

components/post_view/post_list.jsx

@@ -21,9 +21,6 @@ const POSTS_PER_PAGE = Constants.POST_CHUNK_SIZE / 2;
 const MAX_NUMBER_OF_AUTO_RETRIES = 3;
 
 const MAX_EXTRA_PAGES_LOADED = 10;
-const OVERSCAN_COUNT_BACKWARD = window.OVERSCAN_COUNT_BACKWARD || 50; // Exposing the value for PM to test will be removed soon
-const OVERSCAN_COUNT_FORWARD = window.OVERSCAN_COUNT_FORWARD || 100; // Exposing the value for PM to test will be removed soon
-const HEIGHT_TRIGGER_FOR_MORE_POSTS = window.HEIGHT_TRIGGER_FOR_MORE_POSTS || 1000; // Exposing the value for PM to test will be removed soon
 
 export default class PostList extends React.PureComponent {
  static propTypes = {
@@ -300,7 +297,7 @@ export default class PostList extends React.PureComponent {
  onScroll = ({scrollDirection, scrollOffset, scrollUpdateWasRequested}) => {
  const isNotLoadingPosts = !this.state.postsLoading && !this.loadingPosts;
  const didUserScrollBackwards = scrollDirection === 'backward' && !scrollUpdateWasRequested;
- const isOffsetWithInRange = scrollOffset < HEIGHT_TRIGGER_FOR_MORE_POSTS;
+ const isOffsetWithInRange = scrollOffset < 1000;
  if (isNotLoadingPosts && didUserScrollBackwards && isOffsetWithInRange && !this.state.atEnd) {
  this.loadingPosts = true;
  this.loadMorePosts();
@@ -474,8 +471,7 @@ export default class PostList extends React.PureComponent {
  itemCount={this.state.postListIds.length}
  itemData={this.state.postListIds}
  itemKey={this.itemKey}
- overscanCountForward={OVERSCAN_COUNT_FORWARD}
- overscanCountBackward={OVERSCAN_COUNT_BACKWARD}
+ overscanCount={100}
  onScroll={this.onScroll}
  onItemsRendered={this.onItemsRendered}
  initScrollToIndex={this.initScrollToIndex}

package.json

@@ -52,7 +52,7 @@
  "react-select": "2.4.1",
  "react-transition-group": "2.6.0",
  "react-virtualized-auto-sizer": "^1.0.2",
- "react-window": "github:sudheerDev/react-window#e1c298a26c7db32253ba332bc2057dd242d5d8cd",
+ "react-window": "github:sudheerDev/react-window#ccf30388a1a6a7582e0d0573d4cd24d5776ebbaa",
  "rebound": "0.1.0",
  "redux": "4.0.1",
  "redux-batched-actions": "0.4.1",