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

chrome/browser/chromeos/display/display_preferences.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 "chrome/browser/chromeos/display/display_preferences.h"
 
 #include <stddef.h>
 
 #include "ash/display/display_layout_store.h"
 #include "ash/display/display_manager.h"
@@ skipping 116 matching lines @@
       std::vector<std::string> ids = base::SplitString(
           it.key(), ",", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
       int64_t id1 = gfx::Display::kInvalidDisplayID;
       int64_t id2 = gfx::Display::kInvalidDisplayID;
       if (!base::StringToInt64(ids[0], &id1) ||
           !base::StringToInt64(ids[1], &id2) ||
           id1 == gfx::Display::kInvalidDisplayID ||
           id2 == gfx::Display::kInvalidDisplayID) {
         continue;
       }
-      layout_store->RegisterLayoutForDisplayIdPair(id1, id2, layout);
+      layout_store->RegisterLayoutForDisplayIdList(id1, id2, layout);
     }
   }
 }
 
 void LoadDisplayProperties() {
   PrefService* local_state = g_browser_process->local_state();
   const base::DictionaryValue* properties = local_state->GetDictionary(
       prefs::kDisplayProperties);
   for (base::DictionaryValue::Iterator it(*properties);
        !it.IsAtEnd(); it.Advance()) {
@@ skipping 55 matching lines @@
     return;
 
   int rotation = gfx::Display::ROTATE_0;
   if (!properties->GetInteger("orientation", &rotation))
     return;
 
   GetDisplayManager()->RegisterDisplayRotationProperties(rotation_lock,
       static_cast<gfx::Display::Rotation>(rotation));
 }
 
-void StoreDisplayLayoutPref(const ash::DisplayIdPair& pair,
+void StoreDisplayLayoutPref(const ash::DisplayIdList& list,
                             const ash::DisplayLayout& display_layout) {
-  std::string name =
-      base::Int64ToString(pair.first) + "," + base::Int64ToString(pair.second);
+  std::string name = ash::DisplayIdListToString(list);
 
   PrefService* local_state = g_browser_process->local_state();
   DictionaryPrefUpdate update(local_state, prefs::kSecondaryDisplays);
   base::DictionaryValue* pref_data = update.Get();
   scoped_ptr<base::Value> layout_value(new base::DictionaryValue());
   if (pref_data->HasKey(name)) {
     base::Value* value = NULL;
     if (pref_data->Get(name, &value) && value != NULL)
       layout_value.reset(value->DeepCopy());
   }
   if (ash::DisplayLayout::ConvertToValue(display_layout, layout_value.get()))
     pref_data->Set(name, layout_value.release());
 }
 
 void StoreCurrentDisplayLayoutPrefs() {
   ash::DisplayManager* display_manager = GetDisplayManager();
   if (!UserCanSaveDisplayPreference() ||
       display_manager->num_connected_displays() < 2) {
     return;
   }
 
-  ash::DisplayIdPair pair = display_manager->GetCurrentDisplayIdPair();
+  ash::DisplayIdList pair = display_manager->GetCurrentDisplayIdList();
   ash::DisplayLayout display_layout =
       display_manager->layout_store()->GetRegisteredDisplayLayout(pair);
   StoreDisplayLayoutPref(pair, display_layout);
 }
 
 void StoreCurrentDisplayProperties() {
   ash::DisplayManager* display_manager = GetDisplayManager();
   PrefService* local_state = g_browser_process->local_state();
 
   DictionaryPrefUpdate update(local_state, prefs::kDisplayProperties);
@@ skipping 137 matching lines @@
       ash::Shell::GetInstance()->display_configurator()->SetInitialDisplayPower(
           power_state);
     }
   }
 }
 
 // Stores the display layout for given display pairs.
 void StoreDisplayLayoutPrefForTest(int64_t id1,
                                    int64_t id2,
                                    const ash::DisplayLayout& layout) {
-  StoreDisplayLayoutPref(ash::CreateDisplayIdPair(id1, id2), layout);
+  StoreDisplayLayoutPref(ash::CreateDisplayIdList(id1, id2), layout);
 }
 
 // Stores the given |power_state|.
 void StoreDisplayPowerStateForTest(DisplayPowerState power_state) {
   StoreDisplayPowerState(power_state);
 }
 
 }  // namespace chromeos