Fixed scrollview inset when RN view is embedded in another view

This happened to me mainly in modal view controllers on iOS 13, where the view controller is floating and does not start from the top.

Libraries/Components/Keyboard/KeyboardAvoidingView.js

@@ -118,7 +118,28 @@ class KeyboardAvoidingView extends React.Component<Props, State> {
 
   _onLayout = (event: ViewLayoutEvent) => {
     this._frame = event.nativeEvent.layout;
-    if (!this._initialFrameHeight) {
+
+    let isInitial = !this._initialFrameHeight;
+
+    if (this.viewRef.current !== null) {
+      // Try to measure inside the window, not the view controller
+      this.viewRef.current.measureInWindow((x, y, width, height) => {
+        const frame: ViewLayout = {
+          x: x,
+          y: y,
+          width: width,
+          height: height,
+        };
+        this._frame = frame;
+
+        if (isInitial) {
+          // save the initial frame height, before the keyboard is visible
+          this._initialFrameHeight = frame.height;
+        }
+      });
+    }
+
+    if (isInitial) {
       // save the initial frame height, before the keyboard is visible
       this._initialFrameHeight = this._frame.height;
     }