mus: Remove unnecessary const from property TypeConverter templates

mash/wm/user_window_controller_impl.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 "mash/wm/user_window_controller_impl.h"
 
 #include "components/mus/public/cpp/property_type_converters.h"
 #include "components/mus/public/cpp/window.h"
 #include "components/mus/public/cpp/window_property.h"
 #include "components/mus/public/cpp/window_tree_connection.h"
@@ skipping 14 matching lines @@
                mus::mojom::WindowManager::kWindowTitle_Property));
   }
   return mojo::String(std::string());
 }
 
 // Get the serialized app icon bitmap from a mus::Window.
 mojo::Array<uint8_t> GetWindowAppIcon(mus::Window* window) {
   if (window->HasSharedProperty(
           mus::mojom::WindowManager::kWindowAppIcon_Property)) {
     return mojo::Array<uint8_t>::From(
-        window->GetSharedProperty<const std::vector<uint8_t>>(
+        window->GetSharedProperty<std::vector<uint8_t>>(
             mus::mojom::WindowManager::kWindowAppIcon_Property));
   }
   return mojo::Array<uint8_t>();
 }
 
 // Returns |window|, or an ancestor thereof, parented to |container|, or null.
 mus::Window* GetTopLevelWindow(mus::Window* window, mus::Window* container) {
   while (window && window->parent() != container)
     window = window->parent();
   return window;
@@ skipping 125 matching lines @@
 }
 
 void UserWindowControllerImpl::FocusUserWindow(uint32_t window_id) {
   mus::Window* window = GetUserWindowContainer()->GetChildById(window_id);
   if (window)
     window->SetFocus();
 }
 
 }  // namespace wm
 }  // namespace mash