Generalize support for per-display shelf prefs.

chrome/browser/ui/ash/chrome_launcher_prefs.h

Index: chrome/browser/ui/ash/chrome_launcher_prefs.h
diff --git a/chrome/browser/ui/ash/chrome_launcher_prefs.h b/chrome/browser/ui/ash/chrome_launcher_prefs.h
index bed9b897f572a5b5d58f331b905f948d9fd8dbcb..2210f1e047041b1355bcf37e6f94c349aa0db9ce 100644
--- a/chrome/browser/ui/ash/chrome_launcher_prefs.h
+++ b/chrome/browser/ui/ash/chrome_launcher_prefs.h
@@ -9,6 +9,8 @@
 
 #include "ash/shelf/shelf_types.h"
 
+class PrefService;
+
 namespace base {
 class DictionaryValue;
 }
@@ -39,11 +41,18 @@ void RegisterChromeLauncherUserPrefs(
 
 base::DictionaryValue* CreateAppDict(const std::string& app_id);
 
-ash::ShelfAlignment AlignmentFromPref(const std::string& value);
-const char* AlignmentToPref(ash::ShelfAlignment alignment);
-
-ash::ShelfAutoHideBehavior AutoHideBehaviorFromPref(const std::string& value);
-const char* AutoHideBehaviorToPref(ash::ShelfAutoHideBehavior behavior);
+// Get or set the shelf auto hide behavior preference for a root window.
+ShelfAutoHideBehavior GetShelfAutoHideBehaviorPref(PrefService* prefs,
+                                                   int64_t display_id);
+void SetShelfAutoHideBehaviorPref(PrefService* prefs,
+                                  int64_t display_id,
+                                  ShelfAutoHideBehavior behavior);
+
+// Get or set the shelf alignment preference for a root window.
+ShelfAlignment GetShelfAlignmentPref(PrefService* prefs, int64_t display_id);
+void SetShelfAlignmentPref(PrefService* prefs,
+                           int64_t display_id,
+                           ShelfAlignment alignment);
 
 }  // namespace ash