Clear the software mirroring display list when adding it to the updated list.

ash/display/display_manager_unittest.cc

 // Copyright (c) 2012 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/display_manager.h"
 
 #include "ash/accelerators/accelerator_commands.h"
 #include "ash/ash_switches.h"
 #include "ash/display/display_info.h"
 #include "ash/display/display_layout_builder.h"
@@ skipping 1466 matching lines @@
 
   // Overscan insets are ignored.
   UpdateDisplay("400x600/o,600x800/o");
   EXPECT_FALSE(display_observer.changed_and_reset());
   EXPECT_EQ("400x600",
             test_api.GetHost()->window()->bounds().size().ToString());
 
   gfx::Screen::GetScreen()->RemoveObserver(&display_observer);
 }
 
+TEST_F(DisplayManagerTest, RotateInSoftwareMirroring) {
+  if (!SupportsMultipleDisplays())
+    return;
+
+  DisplayManager* display_manager = Shell::GetInstance()->display_manager();
+  UpdateDisplay("600x400,500x300");
+  display_manager->SetMirrorMode(true);
+
+  EXPECT_EQ(1U, display_manager->GetNumDisplays());
+  int64_t primary_id = gfx::Screen::GetScreen()->GetPrimaryDisplay().id();
+  display_manager->SetDisplayRotation(primary_id, gfx::Display::ROTATE_180,
+                                      gfx::Display::ROTATION_SOURCE_ACTIVE);
+  display_manager->SetMirrorMode(false);
+}
+
 TEST_F(DisplayManagerTest, SingleDisplayToSoftwareMirroring) {
   if (!SupportsMultipleDisplays())
     return;
   UpdateDisplay("600x400");
 
   DisplayManager* display_manager = Shell::GetInstance()->display_manager();
   display_manager->SetMultiDisplayMode(DisplayManager::MIRRORING);
   UpdateDisplay("600x400,600x400");
 
   EXPECT_TRUE(display_manager->IsInMirrorMode());
@@ skipping 734 matching lines @@
   layout_store->RegisterLayoutForDisplayIdList(list, std::move(old_layout));
   const DisplayLayout& stored = layout_store->GetRegisteredDisplayLayout(list);
 
   EXPECT_EQ(id1, stored.placement_list[0].parent_display_id);
   EXPECT_EQ(id2, stored.placement_list[0].display_id);
 }
 
 #endif  // OS_CHROMEOS
 
 }  // namespace ash