Fixes to WindowTreeHostMus

ui/aura/test/mus/test_window_tree.h

 // 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.
 
 #ifndef UI_AURA_TEST_MUS_TEST_WINDOW_TREE_H_
 #define UI_AURA_TEST_MUS_TEST_WINDOW_TREE_H_
 
 #include <stdint.h>
 
 #include <set>
@@ skipping 49 matching lines @@
 
   // Same as AckSingleChangeOfType(), but doesn't fail if there is more than
   // one change of the specified type.
   bool AckFirstChangeOfType(WindowTreeChangeType type, bool result);
 
   void AckAllChangesOfType(WindowTreeChangeType type, bool result);
 
   bool GetAndRemoveFirstChangeOfType(WindowTreeChangeType type,
                                      uint32_t* change_id);
 
+  size_t GetChangeCountForType(WindowTreeChangeType type);
+
  private:
   struct Change {
     WindowTreeChangeType type;
     uint32_t id;
   };
 
   void OnChangeReceived(
       uint32_t change_id,
       WindowTreeChangeType type = WindowTreeChangeType::OTHER);
 
@@ skipping 94 matching lines @@
   ui::mojom::WindowTreeClient* client_;
 
   mojo::Map<mojo::String, mojo::Array<uint8_t>> last_new_window_properties_;
 
   DISALLOW_COPY_AND_ASSIGN(TestWindowTree);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_TEST_MUS_TEST_WINDOW_TREE_H_