Improve performance of registering font preferences

chrome/browser/ui/prefs/prefs_tab_helper.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/ui/prefs/prefs_tab_helper.h"
 
 #include <string>
 
 #include "base/prefs/overlay_user_pref_store.h"
 #include "base/string_util.h"
@@ skipping 109 matching lines @@
 const int kPrefsToObserveLength = arraysize(kPrefsToObserve);
 
 // Registers a preference under the path |map_name| for each script used for
 // per-script font prefs.  For example, if |map_name| is "fonts.serif", then
 // "fonts.serif.Arab", "fonts.serif.Hang", etc. are registered.
 void RegisterFontFamilyMap(PrefService* prefs, const char* map_name) {
   for (size_t i = 0; i < prefs::kWebKitScriptsForFontFamilyMapsLength; ++i) {
     const char* script = prefs::kWebKitScriptsForFontFamilyMaps[i];
     std::string pref_name_str = base::StringPrintf("%s.%s", map_name, script);
     const char* pref_name = pref_name_str.c_str();
-    if (!prefs->FindPreference(pref_name))
-      prefs->RegisterStringPref(pref_name, "", PrefService::UNSYNCABLE_PREF);
+    prefs->RegisterStringPrefIfNew(pref_name,
+                                   "",
+                                   PrefService::UNSYNCABLE_PREF);
   }
 }
 
 // Registers |obs| to observe per-script font prefs under the path |map_name|.
 void RegisterFontFamilyMapObserver(PrefChangeRegistrar* registrar,
                                    const char* map_name,
                                    content::NotificationObserver* obs) {
   for (size_t i = 0; i < prefs::kWebKitScriptsForFontFamilyMapsLength; ++i) {
     const char* script = prefs::kWebKitScriptsForFontFamilyMaps[i];
     std::string pref_name = base::StringPrintf("%s.%s", map_name, script);
@@ skipping 425 matching lines @@
 
 void PrefsTabHelper::UpdateRendererPreferences() {
   renderer_preferences_util::UpdateFromSystemSettings(
       web_contents_->GetMutableRendererPrefs(), GetProfile());
   web_contents_->GetRenderViewHost()->SyncRendererPrefs();
 }
 
 Profile* PrefsTabHelper::GetProfile() {
   return Profile::FromBrowserContext(web_contents_->GetBrowserContext());
 }