Bug 111139: Deprecate HOMEPAGE option, remove the UI for it, migrate users away from it

chrome/browser/prefs/session_startup_pref.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/prefs/session_startup_pref.h"
 
 #include <string>
 
+#include "base/values.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"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/pref_names.h"
 
 #if defined(OS_MACOSX)
 #include "chrome/browser/ui/cocoa/window_restore_utils.h"
 #endif
 
 namespace {
 
 // For historical reasons the enum and value registered in the prefs don't line
 // up. These are the values registered in prefs.
-const int kPrefValueHomePage = 0;
+const int kPrefValueHomePage = 0;  // Deprecated
 const int kPrefValueLast = 1;
 const int kPrefValueURLs = 4;
 const int kPrefValueNewTab = 5;
 
 // Converts a SessionStartupPref::Type to an integer written to prefs.
 int TypeToPrefValue(SessionStartupPref::Type type) {
   switch (type) {
-    case SessionStartupPref::HOMEPAGE: return kPrefValueHomePage;
     case SessionStartupPref::LAST:     return kPrefValueLast;
     case SessionStartupPref::URLS:     return kPrefValueURLs;
     default:                           return kPrefValueNewTab;
   }
 }
 
+void SetNewUrlList(PrefService* prefs) {
+  ListValue new_url_pref_list;
+  StringValue* home_page = new StringValue(prefs->GetString(prefs::kHomePage));
+  new_url_pref_list.Append(home_page);
+  prefs->Set(prefs::kURLsToRestoreOnStartup, new_url_pref_list);
+}
+
 }  // namespace
 
 // static
 void SessionStartupPref::RegisterUserPrefs(PrefService* prefs) {
 #if defined(OS_CHROMEOS)
   SessionStartupPref::Type type = SessionStartupPref::LAST;
 #else
   SessionStartupPref::Type type = SessionStartupPref::DEFAULT;
 #endif
 
@@ skipping 46 matching lines @@
   DCHECK(profile);
   return GetStartupPref(profile->GetPrefs());
 }
 
 // static
 SessionStartupPref SessionStartupPref::GetStartupPref(PrefService* prefs) {
   DCHECK(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) {

[Dan Beam, 2012/03/02 22:18:08]

how does one ever delete this code?

[Tyler Breisacher (Chromium), 2012/03/02 22:35:54]

If all users have upgraded to a version that has this change, and opened Chrome
at least once, then it should be safe to delete this. If we wanted to get rid of
this in, say, Chrome 20, then I think the only risk would be someone who
installed, say, Chrome 17, then upgraded to Chrome 20 without ever opening
Chrome 18 or Chrome 19. What do you suggest?

+    prefs->SetInteger(prefs::kRestoreOnStartup, kPrefValueURLs);
+    pref.type = SessionStartupPref::URLS;
+    SetNewUrlList(prefs);
+  }
+
   // Always load the urls, even if the pref type isn't URLS. This way the
   // preferences panels can show the user their last choice.
   const ListValue* url_pref_list = prefs->GetList(
       prefs::kURLsToRestoreOnStartup);
   if (url_pref_list) {
     for (size_t i = 0; i < url_pref_list->GetSize(); ++i) {
       Value* value = NULL;
       if (url_pref_list->Get(i, &value)) {
         std::string url_text;
         if (value->GetAsString(&url_text)) {
@@ skipping 30 matching lines @@
     case kPrefValueLast:     return SessionStartupPref::LAST;
     case kPrefValueURLs:     return SessionStartupPref::URLS;
     case kPrefValueHomePage: return SessionStartupPref::HOMEPAGE;
     default:                 return SessionStartupPref::DEFAULT;
   }
 }
 
 SessionStartupPref::SessionStartupPref(Type type) : type(type) {}
 
 SessionStartupPref::~SessionStartupPref() {}