Use list instead of pair to represent the set of displays.

ash/sticky_keys/sticky_keys_overlay_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/sticky_keys/sticky_keys_overlay.h"
 
 #include "ash/display/display_manager.h"
 #include "ash/display/window_tree_host_manager.h"
 #include "ash/shell.h"
 #include "ash/sticky_keys/sticky_keys_controller.h"
@@ skipping 28 matching lines @@
   EXPECT_EQ(STICKY_KEY_STATE_LOCKED,
             overlay.GetModifierKeyState(ui::EF_COMMAND_DOWN));
 }
 
 // This test addresses the crash report at crbug.com/435600, speculated to be
 // caused by using sticky keys with multiple displays.
 TEST_F(StickyKeysOverlayTest, OverlayNotDestroyedAfterDisplayRemoved) {
   // Add a secondary display to the left of the primary one.
   UpdateDisplay("1280x1024,1980x1080");
   DisplayManager* display_manager = Shell::GetInstance()->display_manager();
-  DisplayIdPair display_ids = display_manager->GetCurrentDisplayIdPair();
-  int64_t primary_display_id = display_ids.first;
-  int64_t secondary_display_id = display_ids.second;
+  DisplayIdList display_ids = display_manager->GetCurrentDisplayIdList();
+  int64_t primary_display_id = display_ids[0];
+  int64_t secondary_display_id = display_ids[1];
   display_manager->SetLayoutForCurrentDisplays(
       DisplayLayout(DisplayLayout::LEFT, 0));
 
   // The overlay should belong to the secondary root window.
   StickyKeysOverlay overlay;
   views::Widget* overlay_widget = overlay.GetWidgetForTesting();
   WindowTreeHostManager* window_tree_host_manager =
       Shell::GetInstance()->window_tree_host_manager();
   EXPECT_EQ(
       window_tree_host_manager->GetRootWindowForDisplayId(secondary_display_id),
@@ skipping 11 matching lines @@
             overlay.GetModifierKeyState(ui::EF_SHIFT_DOWN));
   overlay.SetModifierKeyState(ui::EF_SHIFT_DOWN, STICKY_KEY_STATE_DISABLED);
   EXPECT_EQ(STICKY_KEY_STATE_DISABLED,
             overlay.GetModifierKeyState(ui::EF_SHIFT_DOWN));
 }
 
 // Additional sticky key overlay tests that depend on chromeos::EventRewriter
 // are now in chrome/browser/chromeos/events/event_rewriter_unittest.cc .
 
 }  // namespace ash