Sonar tag for skipping empty view groups in layout target mode

Summary:
I think it's somewhat common to have large containers that can hold future views, especially fragments. The problem is the presence of these containers can block the layout inspector's "target" mode.

I found out from cekkaewnumchai that Flipper does in fact return multiple results from the pick, but I think it could still be helpful to have this new tag since it is more convenient than having to do the secondary drill down each time.

Reviewed By: jknoxville

Differential Revision: D22284972

fbshipit-source-id: 1a2826ec746e4f31690db33ed72815ae168bffab

android/src/main/java/com/facebook/flipper/plugins/inspector/descriptors/ViewGroupDescriptor.java

@@ -294,12 +294,31 @@ public class ViewGroupDescriptor extends NodeDescriptor<ViewGroup> {
   }
 
   private static boolean shouldSkip(View view) {
-    Object tag = view.getTag(R.id.flipper_skip_view_traversal);
-    if (!(tag instanceof Boolean)) {
-      return false;
+    if (hasTag(view, R.id.flipper_skip_view_traversal)) {
+      return true;
     }
 
-    return (Boolean) tag;
+    if (view instanceof ViewGroup
+        && hasTag(view, R.id.flipper_skip_empty_view_group_traversal)
+        && !hasVisibleChildren((ViewGroup) view)) {
+      return true;
+    }
+
+    return false;
+  }
+
+  private static boolean hasTag(View view, int id) {
+    Object tag = view.getTag(id);
+    return tag instanceof Boolean && (Boolean) tag;
+  }
+
+  private static boolean hasVisibleChildren(ViewGroup viewGroup) {
+    for (int i = 0; i < viewGroup.getChildCount(); i++) {
+      if (viewGroup.getChildAt(i).getVisibility() == View.VISIBLE) {
+        return true;
+      }
+    }
+    return false;
   }
 
   @Override

android/src/main/res/values/ids.xml

@@ -8,4 +8,5 @@
 
 <resources>
   <item type="id" name="flipper_skip_view_traversal"/>
+  <item type="id" name="flipper_skip_empty_view_group_traversal"/>
 </resources>