Migrate startup URLs pref.

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/metrics/histogram.h"
 #include "base/prefs/pref_service.h"
+#include "base/time/time.h"
 #include "base/values.h"
 #include "base/version.h"
 #include "chrome/browser/prefs/scoped_user_pref_update.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/common/net/url_fixer_upper.h"
 #include "chrome/common/pref_names.h"
 #include "components/user_prefs/pref_registry_syncable.h"
 
 #if defined(OS_MACOSX)
 #include "chrome/browser/ui/cocoa/window_restore_utils.h"
 #endif
 
 namespace {
 
+enum StartupURLsMigrationMetrics {
+  STARTUP_URLS_MIGRATION_METRICS_STARTED,
+  STARTUP_URLS_MIGRATION_METRICS_DELETED,
+  STARTUP_URLS_MIGRATION_METRICS_RESET,
+  STARTUP_URLS_MIGRATION_METRICS_MAX,
+};
+
 // Converts a SessionStartupPref::Type to an integer written to prefs.
 int TypeToPrefValue(SessionStartupPref::Type type) {
   switch (type) {
     case SessionStartupPref::LAST: return SessionStartupPref::kPrefValueLast;
     case SessionStartupPref::URLS: return SessionStartupPref::kPrefValueURLs;
     default:                       return SessionStartupPref::kPrefValueNewTab;
   }
 }
 
 void SetNewURLList(PrefService* prefs) {
@@ skipping 21 matching lines @@
 
 // static
 void SessionStartupPref::RegisterProfilePrefs(
     user_prefs::PrefRegistrySyncable* registry) {
   registry->RegisterIntegerPref(
       prefs::kRestoreOnStartup,
       TypeToPrefValue(GetDefaultStartupType()),
       user_prefs::PrefRegistrySyncable::SYNCABLE_PREF);
   registry->RegisterListPref(prefs::kURLsToRestoreOnStartup,
                              user_prefs::PrefRegistrySyncable::SYNCABLE_PREF);
+  registry->RegisterListPref(prefs::kURLsToRestoreOnStartupOld,
+                             user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
   registry->RegisterBooleanPref(
       prefs::kRestoreOnStartupMigrated,
       false,
       user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
+  registry->RegisterDoublePref(
+      prefs::kRestoreStartupURLsMigrated,
+      false,
+      user_prefs::PrefRegistrySyncable::UNSYNCABLE_PREF);
 }
 
 // static
 SessionStartupPref::Type SessionStartupPref::GetDefaultStartupType() {
 #if defined(OS_CHROMEOS)
   return SessionStartupPref::LAST;
 #else
   return SessionStartupPref::DEFAULT;
 #endif
 }
@@ skipping 50 matching lines @@
   const ListValue* url_list = prefs->GetList(prefs::kURLsToRestoreOnStartup);
   URLListToPref(url_list, &pref);
 
   return pref;
 }
 
 // static
 void SessionStartupPref::MigrateIfNecessary(PrefService* prefs) {
   DCHECK(prefs);
 
+  // Check if we need to migrate the old version of the startup URLs preference
+  // to the new name, and also send metrics about the migration.
+  const base::ListValue* old_startup_urls =
+      prefs->GetList(prefs::kURLsToRestoreOnStartupOld);
+  if (!prefs->GetUserPrefValue(prefs::kRestoreStartupURLsMigrated)) {
+    // Seems like we never migrated, do it if necessary.
+    if (!prefs->GetUserPrefValue(prefs::kURLsToRestoreOnStartup)) {
+      if (old_startup_urls && old_startup_urls->GetSize() > 0) {
+        prefs->Set(prefs::kURLsToRestoreOnStartup, *old_startup_urls);
+        prefs->Set(prefs::kURLsToRestoreOnStartupOld, base::ListValue());
+      }
+      UMA_HISTOGRAM_ENUMERATION(
+          "Settings.StartupURLsMigration",
+          STARTUP_URLS_MIGRATION_METRICS_STARTED,
+          STARTUP_URLS_MIGRATION_METRICS_MAX);
+    } else {
+      // We migrated but the migration data got deleted somehow.
+      UMA_HISTOGRAM_ENUMERATION(
+          "Settings.StartupURLsMigration",
+          STARTUP_URLS_MIGRATION_METRICS_DELETED,
+          STARTUP_URLS_MIGRATION_METRICS_MAX);
+    }
+    prefs->SetDouble(prefs::kRestoreStartupURLsMigrated,
+                     base::Time::Now().ToDoubleT());
+  } else if (old_startup_urls && old_startup_urls->GetSize() > 0) {
+    // Migration needs to be reset.
+    prefs->Set(prefs::kURLsToRestoreOnStartupOld, base::ListValue());
+    base::Time last_migration_time = base::Time::FromDoubleT(prefs->GetDouble(
+        prefs::kRestoreStartupURLsMigrated));
+    base::Time now = base::Time::Now();
+    prefs->SetDouble(prefs::kRestoreStartupURLsMigrated, now.ToDoubleT());
+    DCHECK(now > last_migration_time);
+    HISTOGRAM_CUSTOM_TIMES("Settings.StartupURLsResetTime",
+                           now - last_migration_time,

[robertshield, 2013/10/04 15:16:15]

in theory, this could be negative. What's the effect on the uma metric when that
happens?

[MAD, 2013/10/04 19:31:22]

I just tried it and it would go in the 0 bucket (if the UMA server reacts like
chrome://histograms).

If you prefer we could also make it explicit, e.g., now > last_migration_time ?
now - last_migration_time : 0

+                           base::TimeDelta::FromDays(0),
+                           base::TimeDelta::FromDays(7),
+                           50);
+    UMA_HISTOGRAM_ENUMERATION(
+        "Settings.StartupURLsMigration",
+        STARTUP_URLS_MIGRATION_METRICS_RESET,
+        STARTUP_URLS_MIGRATION_METRICS_MAX);
+  }
+
   if (!prefs->GetBoolean(prefs::kRestoreOnStartupMigrated)) {
-    // Read existing values
+    // Read existing values.
     const base::Value* homepage_is_new_tab_page_value =
         prefs->GetUserPrefValue(prefs::kHomePageIsNewTabPage);
     bool homepage_is_new_tab_page = true;
     if (homepage_is_new_tab_page_value) {
       if (!homepage_is_new_tab_page_value->GetAsBoolean(
               &homepage_is_new_tab_page))
         NOTREACHED();
     }
 
     const base::Value* restore_on_startup_value =
@@ skipping 81 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() {}