Fix homepage migration for users who never changed their settings.

chrome/browser/prefs/session_startup_pref.cc

Index: chrome/browser/prefs/session_startup_pref.cc
diff --git a/chrome/browser/prefs/session_startup_pref.cc b/chrome/browser/prefs/session_startup_pref.cc
index 447df6523efc57b16e18fcdbf7e666bb4dc04e77..131ece4227ce802d75c24691940e6fab0bc7c0a9 100644
--- a/chrome/browser/prefs/session_startup_pref.cc
+++ b/chrome/browser/prefs/session_startup_pref.cc
@@ -70,6 +70,9 @@ void SessionStartupPref::RegisterUserPrefs(PrefService* prefs) {
                              PrefService::SYNCABLE_PREF);
   prefs->RegisterListPref(prefs::kURLsToRestoreOnStartup,
                           PrefService::SYNCABLE_PREF);
+  prefs->RegisterBooleanPref(prefs::kRestoreOnStartupMigrated,
+                             false,
+                             PrefService::UNSYNCABLE_PREF);
 }
 
 // static
@@ -132,14 +135,26 @@ SessionStartupPref SessionStartupPref::GetStartupPref(PrefService* prefs) {
   SessionStartupPref pref(
       PrefValueToType(prefs->GetInteger(prefs::kRestoreOnStartup)));
 
-  // Migrate from "Open the home page" to "Open the following URLs". If the user
-  // had the "Open the homepage" option selected, then we need to switch them to
-  // "Open the following URLs" and set the list of URLs to a list containing
-  // just the user's homepage.
-  if (pref.type == SessionStartupPref::HOMEPAGE) {
-    prefs->SetInteger(prefs::kRestoreOnStartup, kPrefValueURLs);
-    pref.type = SessionStartupPref::URLS;
-    SetNewURLList(prefs);
+  if (!prefs->GetBoolean(prefs::kRestoreOnStartupMigrated)) {

[Ivan Korotkov, 2012/04/17 09:27:51]

Could you move the migration to a separate function and then call it from
ProtectedPrefsWatcher::EnsurePrefsMigration() instead of GetStartupPref()?

[Tyler Breisacher (Chromium), 2012/04/17 19:54:33]

Done.

+    // Migrate from "Open the home page" to "Open the following URLs". If the
+    // user had the "Open the home page" option selected, switch them to "Open
+    // the following URLs" and set the list of URLs to a one-item list
+    // containing their homepage.
+    if (pref.type == SessionStartupPref::HOMEPAGE ||
+        (!prefs->HasPrefPath(prefs::kRestoreOnStartup) &&
+         !prefs->GetBoolean(prefs::kHomePageIsNewTabPage))) {
+
+      if (prefs->GetBoolean(prefs::kHomePageIsNewTabPage)) {

[Mattias Nissler (ping if slow), 2012/04/17 09:54:48]

These values may still come from policy, in which case you write policy-supplied
data to the user prefs. Bad. You probably want another check on whether the
stuff you migrate is actually coming from user prefs. Alternatively, add code to
pull actual user prefs from the PrefService regardless of whether the effective
pref value comes from some other PrefStore.

[Tyler Breisacher (Chromium), 2012/04/17 19:54:33]

Done.

+        prefs->SetInteger(prefs::kRestoreOnStartup, kPrefValueNewTab);
+        pref.type = SessionStartupPref::DEFAULT;
+      } else {
+        prefs->SetInteger(prefs::kRestoreOnStartup, kPrefValueURLs);
+        pref.type = SessionStartupPref::URLS;
+        SetNewURLList(prefs);
+      }
+    }
+
+    prefs->SetBoolean(prefs::kRestoreOnStartupMigrated, true);
   }
 
   // Always load the urls, even if the pref type isn't URLS. This way the