Port more focus controller unit tests and fix our focus rules.

mojo/services/window_manager/basic_focus_rules.h

Index: mojo/services/window_manager/basic_focus_rules.h
diff --git a/mojo/services/window_manager/basic_focus_rules.h b/mojo/services/window_manager/basic_focus_rules.h
index e5db4de4664d52f4f381a73d74b31f4c2bee4f8f..e243ee046dd956b9405829f3f4023b1a9f6d0cde 100644
--- a/mojo/services/window_manager/basic_focus_rules.h
+++ b/mojo/services/window_manager/basic_focus_rules.h
@@ -15,10 +15,6 @@ class View;
 //
 // This is intended to be a user supplyable, subclassable component passed to
 // WindowManagerApp, allowing for the creation of other window managers.
-//
-// TODO(erg): This was a straight move of the minimal focus rules from when
-// WindowManagerApp directly used the wm::FocusController. This implementation
-// is very incomplete. crbug.com/431047
 class BasicFocusRules : public FocusRules {
  public:
   BasicFocusRules(mojo::View* window_container);
@@ -26,6 +22,7 @@ class BasicFocusRules : public FocusRules {
 
  protected:
   // Overridden from mojo::FocusRules:
+  bool SupportsChildActivation(mojo::View* view) const override;
   bool IsToplevelView(mojo::View* view) const override;
   bool CanActivateView(mojo::View* view) const override;
   bool CanFocusView(mojo::View* view) const override;