Implement cursor changing on Mushrome

ash/display/mirror_window_controller.cc

 // Copyright (c) 2013 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 "ash/display/mirror_window_controller.h"
 
 #include <utility>
 
 #if defined(USE_X11)
 #include <X11/extensions/XInput2.h>
@@ skipping 254 matching lines @@
         ++iter;
       }
     }
   }
 }
 
 void MirrorWindowController::UpdateWindow() {
   if (mirroring_host_info_map_.empty())
     return;
   display::DisplayManager* display_manager = Shell::Get()->display_manager();
+  display::Screen* screen = display::Screen::GetScreen();
+
   std::vector<display::ManagedDisplayInfo> display_info_list;
-  for (auto& pair : mirroring_host_info_map_)
-    display_info_list.push_back(display_manager->GetDisplayInfo(pair.first));
+  // Prune the window on the removed displays.
+  for (auto& pair : mirroring_host_info_map_) {
+    MirroringHostInfo* info = pair.second;
+    if (screen
+            ->GetDisplayNearestWindow(
+                info->ash_host->AsWindowTreeHost()->window())
+            .is_valid()) {
+      display_info_list.push_back(display_manager->GetDisplayInfo(pair.first));
+    }
+  }
   UpdateWindow(display_info_list);
 }
 
 void MirrorWindowController::CloseIfNotNecessary() {
   display::DisplayManager::MultiDisplayMode new_mode =
       GetCurrentMultiDisplayMode();
-  if (multi_display_mode_ != new_mode)
+  if (multi_display_mode_ != new_mode) {
     Close(true);
-  multi_display_mode_ = new_mode;
+    multi_display_mode_ = new_mode;
+  } else {
+    UpdateWindow();
+  }
 }
 
 void MirrorWindowController::Close(bool delay_host_deletion) {
   for (auto& info : mirroring_host_info_map_)
     CloseAndDeleteHost(info.second, delay_host_deletion);
 
   mirroring_host_info_map_.clear();
   if (reflector_) {
     aura::Env::GetInstance()->context_factory_private()->RemoveReflector(
         reflector_.get());
@@ skipping 87 matching lines @@
   // EventProcessor may be accessed after this call if the mirroring window
   // was deleted as a result of input event (e.g. shortcut), so don't delete
   // now.
   if (delay_host_deletion)
     base::ThreadTaskRunnerHandle::Get()->DeleteSoon(FROM_HERE, host_info);
   else
     delete host_info;
 }
 
 }  // namespace ash