mus: Allow the WM to specify the windows that can have active children.

components/mus/ws/focus_controller_unittest.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "components/mus/ws/focus_controller.h"
 
+#include "components/mus/ws/focus_controller_delegate.h"
 #include "components/mus/ws/focus_controller_observer.h"
 #include "components/mus/ws/server_window.h"
 #include "components/mus/ws/test_server_window_delegate.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace mus {
 
 namespace ws {
 namespace {
 
-class TestFocusControllerObserver : public FocusControllerObserver {
+class TestFocusControllerObserver : public FocusControllerObserver,
+                                    public FocusControllerDelegate {
  public:
   TestFocusControllerObserver()
       : change_count_(0u),
         old_focused_window_(nullptr),
         new_focused_window_(nullptr) {}
 
   void ClearAll() {
     change_count_ = 0u;
     old_focused_window_ = nullptr;
     new_focused_window_ = nullptr;
   }
   size_t change_count() const { return change_count_; }
   ServerWindow* old_focused_window() { return old_focused_window_; }
   ServerWindow* new_focused_window() { return new_focused_window_; }
 
  private:
+  // FocusControllerDelegate:
+  bool CanHaveActiveChildren(ServerWindow* window) const override {
+    return true;
+  }
   // FocusControllerObserver:
+  void OnActivationChanged(ServerWindow* old_active_window,
+                           ServerWindow* new_active_window) override {}
   void OnFocusChanged(FocusControllerChangeSource source,
                       ServerWindow* old_focused_window,
                       ServerWindow* new_focused_window) override {
     if (source == FocusControllerChangeSource::EXPLICIT)
       return;
 
     change_count_++;
     old_focused_window_ = old_focused_window;
     new_focused_window_ = new_focused_window;
   }
@@ skipping 13 matching lines @@
   server_window_delegate.set_root_window(&root);
   root.SetVisible(true);
   ServerWindow child(&server_window_delegate, WindowId());
   child.SetVisible(true);
   root.Add(&child);
   ServerWindow child_child(&server_window_delegate, WindowId());
   child_child.SetVisible(true);
   child.Add(&child_child);
 
   TestFocusControllerObserver focus_observer;
-  FocusController focus_controller;
+  FocusController focus_controller(&focus_observer);
   focus_controller.AddObserver(&focus_observer);
 
   focus_controller.SetFocusedWindow(&child_child);
   EXPECT_EQ(0u, focus_observer.change_count());
 
   // Remove the ancestor of the focused window, focus should go to the |root|.
   root.Remove(&child);
   EXPECT_EQ(1u, focus_observer.change_count());
   EXPECT_EQ(&root, focus_observer.new_focused_window());
   EXPECT_EQ(&child_child, focus_observer.old_focused_window());
@@ skipping 29 matching lines @@
   EXPECT_EQ(1u, focus_observer.change_count());
   EXPECT_EQ(&root, focus_observer.new_focused_window());
   EXPECT_EQ(&child_child, focus_observer.old_focused_window());
   focus_observer.ClearAll();
   focus_controller.RemoveObserver(&focus_observer);
 }
 
 }  // namespace ws
 
 }  // namespace mus