react-native-web+0.19.12+005+osr-improvement.patch

diff --git a/node_modules/react-native-web/dist/vendor/react-native/VirtualizedList/index.js b/node_modules/react-native-web/dist/vendor/react-native/VirtualizedList/index.js
index b05da08..80aea85 100644
--- a/node_modules/react-native-web/dist/vendor/react-native/VirtualizedList/index.js
+++ b/node_modules/react-native-web/dist/vendor/react-native/VirtualizedList/index.js
@@ -332,7 +332,7 @@ class VirtualizedList extends StateSafePureComponent {
       zoomScale: 1
     };
     this._scrollRef = null;
-    this._sentStartForContentLength = 0;
+    this._sentStartForFirstVisibleItemKey = null;
     this._sentEndForContentLength = 0;
     this._totalCellLength = 0;
     this._totalCellsMeasured = 0;
@@ -1397,8 +1397,8 @@ class VirtualizedList extends StateSafePureComponent {
     // Next check if the user just scrolled within the start threshold
     // and call onStartReached only once for a given content length,
     // and only if onEndReached is not being executed
-    else if (onStartReached != null && this.state.cellsAroundViewport.first === 0 && isWithinStartThreshold && this._scrollMetrics.contentLength !== this._sentStartForContentLength) {
-      this._sentStartForContentLength = this._scrollMetrics.contentLength;
+    else if (onStartReached != null && this.state.cellsAroundViewport.first === 0 && isWithinStartThreshold && this.state.firstVisibleItemKey !== this._sentStartForFirstVisibleItemKey) {
+      this._sentStartForFirstVisibleItemKey = this.state.firstVisibleItemKey;
       onStartReached({
         distanceFromStart
       });
@@ -1407,7 +1407,7 @@ class VirtualizedList extends StateSafePureComponent {
     // If the user scrolls away from the start or end and back again,
     // cause onStartReached or onEndReached to be triggered again
     else {
-      this._sentStartForContentLength = isWithinStartThreshold ? this._sentStartForContentLength : 0;
+      this._sentStartForFirstVisibleItemKey = isWithinStartThreshold ? this._sentStartForFirstVisibleItemKey : null;
       this._sentEndForContentLength = isWithinEndThreshold ? this._sentEndForContentLength : 0;
     }
   }
diff --git a/node_modules/react-native-web/src/vendor/react-native/VirtualizedList/index.js b/node_modules/react-native-web/src/vendor/react-native/VirtualizedList/index.js
index 459f017..799a6ee 100644
--- a/node_modules/react-native-web/src/vendor/react-native/VirtualizedList/index.js
+++ b/node_modules/react-native-web/src/vendor/react-native/VirtualizedList/index.js
@@ -1325,7 +1325,7 @@ class VirtualizedList extends StateSafePureComponent<Props, State> {
     zoomScale: 1,
   };
   _scrollRef: ?React.ElementRef<any> = null;
-  _sentStartForContentLength = 0;
+  _sentStartForFirstVisibleItemKey: ?string = null;
   _sentEndForContentLength = 0;
   _totalCellLength = 0;
   _totalCellsMeasured = 0;
@@ -1675,18 +1675,18 @@ class VirtualizedList extends StateSafePureComponent<Props, State> {
       onStartReached != null &&
       this.state.cellsAroundViewport.first === 0 &&
       isWithinStartThreshold &&
-      this._scrollMetrics.contentLength !== this._sentStartForContentLength
+      this.state.firstVisibleItemKey !== this._sentStartForFirstVisibleItemKey
     ) {
-      this._sentStartForContentLength = this._scrollMetrics.contentLength;
+      this._sentStartForFirstVisibleItemKey = this.state.firstVisibleItemKey;
       onStartReached({distanceFromStart});
     }
 
     // If the user scrolls away from the start or end and back again,
     // cause onStartReached or onEndReached to be triggered again
     else {
-      this._sentStartForContentLength = isWithinStartThreshold
-        ? this._sentStartForContentLength
-        : 0;
+      this._sentStartForFirstVisibleItemKey = isWithinStartThreshold
+        ? this._sentStartForFirstVisibleItemKey
+        : null;
       this._sentEndForContentLength = isWithinEndThreshold
         ? this._sentEndForContentLength
         : 0;