Various optimizations to reduce the number of temporary allocations.

chrome/browser/extensions/api/font_settings/font_settings_api.cc

Index: chrome/browser/extensions/api/font_settings/font_settings_api.cc
diff --git a/chrome/browser/extensions/api/font_settings/font_settings_api.cc b/chrome/browser/extensions/api/font_settings/font_settings_api.cc
index cf01a958e33df9ba0d82949357627cf7e80edca3..5a1e90fbe64ff0d8e03d8cba15b36a9c05211a2a 100644
--- a/chrome/browser/extensions/api/font_settings/font_settings_api.cc
+++ b/chrome/browser/extensions/api/font_settings/font_settings_api.cc
@@ -61,8 +61,8 @@ std::string GetFontNamePrefPath(fonts::GenericFamily generic_family_enum,
     script = prefs::kWebKitCommonScript;
   std::string generic_family = fonts::ToString(generic_family_enum);
   return base::StringPrintf(kWebKitFontPrefFormat,
-                            generic_family.c_str(),
-                            script.c_str());
+                            generic_family,
+                            script);
 }
 
 // Returns the localized name of a font so that it can be matched within the
@@ -84,10 +84,14 @@ void RegisterFontFamilyMapObserver(
     PrefChangeRegistrar* registrar,
     const char* map_name,
     const PrefChangeRegistrar::NamedChangeCallback& callback) {
+  std::string pref_name;
+  pref_name.reserve(512);  // Reduces number of grows.
   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);
-    registrar->Add(pref_name.c_str(), callback);
+    pref_name.assign(map_name);
+    pref_name.append(1, '.');
+    pref_name.append(script);
+    registrar->Add(pref_name, callback);

[Nico, 2014/12/03 19:14:39]

This still does not lgtm.

   }
 }
 
@@ -109,21 +113,21 @@ FontSettingsEventRouter::FontSettingsEventRouter(
 
   PrefChangeRegistrar::NamedChangeCallback callback =
       base::Bind(&FontSettingsEventRouter::OnFontFamilyMapPrefChanged,
-                 base::Unretained(this));
-  RegisterFontFamilyMapObserver(&registrar_,
-                                prefs::kWebKitStandardFontFamilyMap, callback);
-  RegisterFontFamilyMapObserver(&registrar_,
-                                prefs::kWebKitSerifFontFamilyMap, callback);
-  RegisterFontFamilyMapObserver(&registrar_,
-                                prefs::kWebKitSansSerifFontFamilyMap, callback);
-  RegisterFontFamilyMapObserver(&registrar_,
-                                prefs::kWebKitFixedFontFamilyMap, callback);
-  RegisterFontFamilyMapObserver(&registrar_,
-                                prefs::kWebKitCursiveFontFamilyMap, callback);
-  RegisterFontFamilyMapObserver(&registrar_,
-                                prefs::kWebKitFantasyFontFamilyMap, callback);
-  RegisterFontFamilyMapObserver(&registrar_,
-                                prefs::kWebKitPictographFontFamilyMap,
+                 base::Unretained(this));
+  RegisterFontFamilyMapObserver(&registrar_,
+                                prefs::kWebKitStandardFontFamilyMap, callback);
+  RegisterFontFamilyMapObserver(&registrar_,
+                                prefs::kWebKitSerifFontFamilyMap, callback);
+  RegisterFontFamilyMapObserver(&registrar_,
+                                prefs::kWebKitSansSerifFontFamilyMap, callback);
+  RegisterFontFamilyMapObserver(&registrar_,
+                                prefs::kWebKitFixedFontFamilyMap, callback);
+  RegisterFontFamilyMapObserver(&registrar_,
+                                prefs::kWebKitCursiveFontFamilyMap, callback);
+  RegisterFontFamilyMapObserver(&registrar_,
+                                prefs::kWebKitFantasyFontFamilyMap, callback);
+  RegisterFontFamilyMapObserver(&registrar_,
+                                prefs::kWebKitPictographFontFamilyMap,
                                 callback);
 }
 
@@ -156,7 +160,7 @@ void FontSettingsEventRouter::OnFontNamePrefChanged(
     const std::string& generic_family,
     const std::string& script) {
   const PrefService::Preference* pref = registrar_.prefs()->FindPreference(
-      pref_name.c_str());
+      pref_name);
   CHECK(pref);
 
   std::string font_name;
@@ -187,7 +191,7 @@ void FontSettingsEventRouter::OnFontPrefChanged(
     const std::string& key,
     const std::string& pref_name) {
   const PrefService::Preference* pref = registrar_.prefs()->FindPreference(
-      pref_name.c_str());
+      pref_name);
   CHECK(pref);
 
   base::ListValue args;
@@ -235,10 +239,10 @@ bool FontSettingsClearFontFunction::RunSync() {
 
   // Ensure |pref_path| really is for a registered per-script font pref.
   EXTENSION_FUNCTION_VALIDATE(
-      GetProfile()->GetPrefs()->FindPreference(pref_path.c_str()));
+      GetProfile()->GetPrefs()->FindPreference(pref_path));
 
   PreferenceAPI::Get(GetProfile())->RemoveExtensionControlledPref(
-      extension_id(), pref_path.c_str(), kExtensionPrefsScopeRegular);
+      extension_id(), pref_path, kExtensionPrefsScopeRegular);
   return true;
 }
 
@@ -252,7 +256,7 @@ bool FontSettingsGetFontFunction::RunSync() {
 
   PrefService* prefs = GetProfile()->GetPrefs();
   const PrefService::Preference* pref =
-      prefs->FindPreference(pref_path.c_str());
+      prefs->FindPreference(pref_path);
 
   std::string font_name;
   EXTENSION_FUNCTION_VALIDATE(
@@ -288,11 +292,11 @@ bool FontSettingsSetFontFunction::RunSync() {
 
   // Ensure |pref_path| really is for a registered font pref.
   EXTENSION_FUNCTION_VALIDATE(
-      GetProfile()->GetPrefs()->FindPreference(pref_path.c_str()));
+      GetProfile()->GetPrefs()->FindPreference(pref_path));
 
   PreferenceAPI::Get(GetProfile())->SetExtensionControlledPref(
       extension_id(),
-      pref_path.c_str(),
+      pref_path,
       kExtensionPrefsScopeRegular,
       new base::StringValue(params->details.font_id));
   return true;