2 files changed, 24 insertions, 10 deletions
diff --git a/chrome/browser/prefs/session_startup_pref.cc b/chrome/browser/prefs/session_startup_pref.cc
index d63767d..bbe96c9 100644
--- a/chrome/browser/prefs/session_startup_pref.cc
+++ b/chrome/browser/prefs/session_startup_pref.cc
@@ -7,6 +7,7 @@
 #include <string>
 
 #include "base/values.h"
+#include "base/version.h"
 #include "chrome/browser/net/url_fixer_upper.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/prefs/scoped_user_pref_update.h"
@@ -72,18 +73,10 @@ void SessionStartupPref::RegisterUserPrefs(PrefService* prefs) {
 // static
 SessionStartupPref::Type SessionStartupPref::GetDefaultStartupType() {
 #if defined(OS_CHROMEOS)
-  SessionStartupPref::Type type = SessionStartupPref::LAST;
+  return SessionStartupPref::LAST;
 #else
-  SessionStartupPref::Type type = SessionStartupPref::DEFAULT;
+  return SessionStartupPref::DEFAULT;
 #endif
-
-#if defined(OS_MACOSX)
-  // Use Lion's system preference, if it is set.
-  if (restore_utils::IsWindowRestoreEnabled())
-    type = SessionStartupPref::LAST;
-#endif
-
-  return type;
 }
 
 // static
@@ -129,6 +122,11 @@ SessionStartupPref SessionStartupPref::GetStartupPref(PrefService* prefs) {
 
   MigrateIfNecessary(prefs);
 
+#if defined(OS_MACOSX)
+  if (restore_utils::IsWindowRestoreEnabled())
+    MigrateMacDefaultPrefIfNecessary(prefs);
+#endif
+
   SessionStartupPref pref(
       PrefValueToType(prefs->GetInteger(prefs::kRestoreOnStartup)));
 
@@ -189,6 +187,18 @@ void SessionStartupPref::MigrateIfNecessary(PrefService* prefs) {
 }
 
 // static
+void SessionStartupPref::MigrateMacDefaultPrefIfNecessary(PrefService* prefs) {
+  DCHECK(prefs);
+  // The default startup pref used to be LAST, now it is DEFAULT. Don't change
+  // the setting for existing profiles (even if the user has never changed it),
+  // but make new profiles default to DEFAULT.
+  bool old_profile_version = Version(prefs->GetString(
+      prefs::kProfileCreatedByVersion)).IsOlderThan("21.0.1180.0");
+  if (old_profile_version && TypeIsDefault(prefs))
+    prefs->SetInteger(prefs::kRestoreOnStartup, kPrefValueLast);
+}
+
+// static
 bool SessionStartupPref::TypeIsManaged(PrefService* prefs) {
   DCHECK(prefs);
   const PrefService::Preference* pref_restore =
diff --git a/chrome/browser/prefs/session_startup_pref.h b/chrome/browser/prefs/session_startup_pref.h
index e1885aa..48e2e114 100644
--- a/chrome/browser/prefs/session_startup_pref.h
+++ b/chrome/browser/prefs/session_startup_pref.h
@@ -58,6 +58,10 @@ struct SessionStartupPref {
   // the same effect.
   static void MigrateIfNecessary(PrefService* prefs);
 
+  // The default startup pref for Mac used to be LAST, now it's DEFAULT. This
+  // migrates old users by writing out the preference explicitly.
+  static void MigrateMacDefaultPrefIfNecessary(PrefService* prefs);
+
   // Whether the startup type and URLs are managed via policy.
   static bool TypeIsManaged(PrefService* prefs);
   static bool URLsAreManaged(PrefService* prefs);