ScrollView, HorizontalScrollView: support null contentOffset

Summary:
According to the Flow types, `contentOffset` is nullable. Support that.

Changelog: [Internal] Fix to (1) support null contentOffset in ScrollView and HorizontalScrollView, added on Android after the last release. (2) Correctly add support for contentOffset in ScrollView (I missed that when adding it to HorizontalScrollView in the previous diff).

Reviewed By: alsun2001

Differential Revision: D21243028

fbshipit-source-id: ebef9a9054a3e4dd88556739e836b7ece48fda12

ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactHorizontalScrollViewManager.java

@@ -303,8 +303,10 @@ public void setFadingEdgeLength(ReactHorizontalScrollView view, int value) {
 
   @ReactProp(name = "contentOffset")
   public void setContentOffset(ReactHorizontalScrollView view, ReadableMap value) {
-    double x = value.getDouble("x");
-    double y = value.getDouble("y");
-    view.reactScrollTo((int) PixelUtil.toPixelFromDIP(x), (int) PixelUtil.toPixelFromDIP(y));
+    if (value != null) {
+      double x = value.getDouble("x");
+      double y = value.getDouble("y");
+      view.reactScrollTo((int) PixelUtil.toPixelFromDIP(x), (int) PixelUtil.toPixelFromDIP(y));
+    }
   }
 }

ReactAndroid/src/main/java/com/facebook/react/views/scroll/ReactScrollViewManager.java

@@ -13,6 +13,7 @@
 import androidx.annotation.Nullable;
 import androidx.core.view.ViewCompat;
 import com.facebook.react.bridge.ReadableArray;
+import com.facebook.react.bridge.ReadableMap;
 import com.facebook.react.bridge.RetryableMountingLayerException;
 import com.facebook.react.common.MapBuilder;
 import com.facebook.react.module.annotations.ReactModule;
@@ -304,6 +305,15 @@ public void setFadingEdgeLength(ReactScrollView view, int value) {
     }
   }
 
+  @ReactProp(name = "contentOffset")
+  public void setContentOffset(ReactScrollView view, ReadableMap value) {
+    if (value != null) {
+      double x = value.getDouble("x");
+      double y = value.getDouble("y");
+      view.reactScrollTo((int) PixelUtil.toPixelFromDIP(x), (int) PixelUtil.toPixelFromDIP(y));
+    }
+  }
+
   @Override
   public Object updateState(
       ReactScrollView view, ReactStylesDiffMap props, @Nullable StateWrapper stateWrapper) {