Allow dynamic enabling/disabling of unified desktop

ash/display/display_util_unittest.cc

 // Copyright 2014 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_util.h"
 
 #include "ash/root_window_controller.h"
 #include "ash/shell.h"
 #include "ash/test/ash_test_base.h"
 #include "ash/test/display_manager_test_api.h"
@@ skipping 80 matching lines @@
   }
 }
 
 TEST_F(DisplayUtilTest, CreateDisplayIdPair) {
   DisplayIdPair pair = CreateDisplayIdPair(10, 1);
   EXPECT_EQ(1, pair.first);
   EXPECT_EQ(10, pair.second);
   pair = CreateDisplayIdPair(10, 100);
   EXPECT_EQ(10, pair.first);
   EXPECT_EQ(100, pair.second);
+  {
+    test::ScopedSetInternalDisplayId set_internal(100);
+    pair = CreateDisplayIdPair(10, 100);
+    EXPECT_EQ(100, pair.first);
+    EXPECT_EQ(10, pair.second);
 
-  test::ScopedSetInternalDisplayId set_internal(100);
-  pair = CreateDisplayIdPair(10, 100);
-  EXPECT_EQ(100, pair.first);
-  EXPECT_EQ(10, pair.second);
+    pair = CreateDisplayIdPair(100, 10);
+    EXPECT_EQ(100, pair.first);
+    EXPECT_EQ(10, pair.second);
+  }
+
+  {
+    test::ScopedSetInternalDisplayId set_internal(10);
+    pair = CreateDisplayIdPair(10, 100);
+    EXPECT_EQ(10, pair.first);
+    EXPECT_EQ(100, pair.second);
+
+    pair = CreateDisplayIdPair(100, 10);
+    EXPECT_EQ(10, pair.first);
+    EXPECT_EQ(100, pair.second);
+  }
 }
 
 }  // namespace