RN: Add Support for `overflow` on Android

Summary:
Adds support for the `overflow` style property on React Native for Android.

This switches overflowing views to be visible by default with the ability to override this at the container level using `overflow: 'hidden'`. This is the same behavior as React Native on iOS.

One major caveat to this solution is that it uses `setClipChildren` which does not extend the hit target to the overflow draw regions. While this is a pitfall, the current state of React Native on Android where `overflow` is hidden by default (which is the opposite of iOS) is also a huge pitfall. But I think this moves us in the right direction because where you *don't* need the touch behavior, you are now able to leverage overflow draws.

Reviewed By: himabindugadupudi

Differential Revision: D8666509

fbshipit-source-id: 5e98e658e16188414016260224caa696b4fbd390

ReactAndroid/src/main/java/com/facebook/react/uimanager/ViewProps.java

@@ -254,8 +254,8 @@ public class ViewProps {
           return map.isNull(BORDER_RIGHT_WIDTH) || map.getDouble(BORDER_RIGHT_WIDTH) == 0d;
         case BORDER_BOTTOM_WIDTH:
           return map.isNull(BORDER_BOTTOM_WIDTH) || map.getDouble(BORDER_BOTTOM_WIDTH) == 0d;
-        case OVERFLOW: // We do nothing with this right now.
-          return true;
+        case OVERFLOW:
+          return map.isNull(OVERFLOW) || map.getString(OVERFLOW) == "visible";
         default:
           return false;
       }

ReactAndroid/src/main/java/com/facebook/react/views/view/ReactViewGroup.java

@@ -112,6 +112,7 @@ public class ReactViewGroup extends ViewGroup implements
 
   public ReactViewGroup(Context context) {
     super(context);
+    setClipChildren(false);
     mDrawingOrderHelper = new ViewGroupDrawingOrderHelper(this);
   }
 
@@ -638,6 +639,7 @@ public class ReactViewGroup extends ViewGroup implements
   }
 
   public void setOverflow(String overflow) {
+    setClipChildren(mOverflow == "hidden");
     mOverflow = overflow;
     invalidate();
   }