Remove background_alias_do_not_use_permission

chrome/common/extensions/permissions/api_permission.cc

Index: chrome/common/extensions/permissions/api_permission.cc
diff --git a/chrome/common/extensions/permissions/api_permission.cc b/chrome/common/extensions/permissions/api_permission.cc
index 884260b36a13e177d437c86c0b6a299ef246b924..3838b8329ad05ca9aa90b3932e90b78d77eb1c56 100644
--- a/chrome/common/extensions/permissions/api_permission.cc
+++ b/chrome/common/extensions/permissions/api_permission.cc
@@ -12,7 +12,6 @@ namespace {
 
 const char kOldUnlimitedStoragePermission[] = "unlimited_storage";
 const char kWindowsPermission[] = "windows";
-const char kTemporaryBackgroundAlias[] = "background_alias_do_not_use";
 
 }  // namespace
 
@@ -187,9 +186,6 @@ void APIPermission::RegisterAllPermissions(
   // Register aliases.
   info->RegisterAlias("unlimitedStorage", kOldUnlimitedStoragePermission);
   info->RegisterAlias("tabs", kWindowsPermission);
-  // TODO(mihaip): Should be removed for the M20 branch, see
-  // http://crbug.com/120447 for more details.
-  info->RegisterAlias("background", kTemporaryBackgroundAlias);
 }
 
 }  // namespace extensions