Fixes bug in handling restacking because of transients

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>
 
 #include "base/macros.h"
 #include "services/ui/public/interfaces/window_tree.mojom.h"
 #include "ui/aura/mus/mus_types.h"
 
 namespace aura {
 
 enum class WindowTreeChangeType {
   ADD_TRANSIENT,
   BOUNDS,
   // Used for both set and release capture.
   CAPTURE,
   FOCUS,
   MODAL,
   NEW_TOP_LEVEL,
   NEW_WINDOW,
   PROPERTY,
   REMOVE_TRANSIENT,
+  REORDER,
   VISIBLE,
 
   // This covers all cases that aren't used in tests.
   OTHER,
 };
 
 struct TransientData {
   Id parent_id;
   Id child_id;
 };
@@ skipping 12 matching lines @@
 
   bool WasEventAcked(uint32_t event_id) const;
 
   mojo::Array<uint8_t> GetLastPropertyValue();
 
   mojo::Map<mojo::String, mojo::Array<uint8_t>> GetLastNewWindowProperties();
 
   // True if at least one function has been called that takes a change id.
   bool has_change() const { return !changes_.empty(); }
 
+  size_t number_of_changes() const { return changes_.size(); }
+
   // Acks all changes with a value of true.
   void AckAllChanges();
 
   // Returns false if there are no, or more than one, changes of the specified
   // type. If there is only one of the matching type it is acked with a result
   // of |result| and true is returned.
   bool AckSingleChangeOfType(WindowTreeChangeType type, bool result);
 
   // Same as AckSingleChangeOfType(), but doesn't fail if there is more than
   // one change of the specified type.
@@ skipping 116 matching lines @@
   mojo::Map<mojo::String, mojo::Array<uint8_t>> last_new_window_properties_;
 
   TransientData transient_data_;
 
   DISALLOW_COPY_AND_ASSIGN(TestWindowTree);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_TEST_MUS_TEST_WINDOW_TREE_H_