Update bool WindowManager::OnWmSetBounds() to match with its desirable behavior.

ash/mus/window_manager.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 ASH_MUS_WINDOW_MANAGER_H_
 #define ASH_MUS_WINDOW_MANAGER_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 116 matching lines @@
 
   // WindowTreeClientDelegate:
   void OnEmbed(ui::Window* root) override;
   void OnEmbedRootDestroyed(ui::Window* root) override;
   void OnLostConnection(ui::WindowTreeClient* client) override;
   void OnPointerEventObserved(const ui::PointerEvent& event,
                               ui::Window* target) override;
 
   // WindowManagerDelegate:
   void SetWindowManagerClient(ui::WindowManagerClient* client) override;
-  bool OnWmSetBounds(ui::Window* window, gfx::Rect* bounds) override;
+  void OnWmSetBounds(ui::Window* window, gfx::Rect* bounds) override;
   bool OnWmSetProperty(
       ui::Window* window,
       const std::string& name,
       std::unique_ptr<std::vector<uint8_t>>* new_data) override;
   ui::Window* OnWmCreateTopLevelWindow(
       std::map<std::string, std::vector<uint8_t>>* properties) override;
   void OnWmClientJankinessChanged(const std::set<ui::Window*>& client_windows,
                                   bool not_responding) override;
   void OnWmNewDisplay(ui::Window* window,
                       const display::Display& display) override;
@@ skipping 32 matching lines @@
   std::map<uint16_t, AcceleratorHandler*> accelerator_handlers_;
   uint16_t next_accelerator_namespace_id_ = 0u;
 
   DISALLOW_COPY_AND_ASSIGN(WindowManager);
 };
 
 }  // namespace mus
 }  // namespace ash
 
 #endif  // ASH_MUS_WINDOW_MANAGER_H_