Change GetAllDisplays() in all screens to return a const vector&.

ui/views/mus/window_manager_connection.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 "ui/views/mus/window_manager_connection.h"
 
 #include <algorithm>
 #include <set>
 #include <utility>
 
@@ skipping 166 matching lines @@
 
   ViewsDelegate::GetInstance()->set_native_widget_factory(base::Bind(
       &WindowManagerConnection::CreateNativeWidgetMus,
       base::Unretained(this),
       std::map<std::string, std::vector<uint8_t>>()));
 }
 
 ui::Window* WindowManagerConnection::GetUiWindowAtScreenPoint(
     const gfx::Point& point) {
   std::map<int64_t, gfx::Point> display_origins;
-  for (display::Display& d : display::Screen::GetScreen()->GetAllDisplays())
+  for (const display::Display& d :
+       display::Screen::GetScreen()->GetAllDisplays())
     display_origins[d.id()] = d.bounds().origin();
 
   const std::set<ui::Window*>& roots = GetRoots();
   std::vector<ui::Window*> windows;
   std::copy(roots.begin(), roots.end(), std::back_inserter(windows));
   return GetWindowFrom(display_origins, windows, point);
 }
 
 void WindowManagerConnection::OnEmbed(ui::Window* root) {}
 
@@ skipping 27 matching lines @@
     const gfx::Point& point) {
   return GetAuraWindowFromUiWindow(GetUiWindowAtScreenPoint(point));
 }
 
 std::unique_ptr<OSExchangeData::Provider>
 WindowManagerConnection::BuildProvider() {
   return base::MakeUnique<aura::OSExchangeDataProviderMus>();
 }
 
 }  // namespace views