Rewrite std::string("") to std::string(), Linux edition.

This patch was generated by running the empty_string clang tool
across the Chromium Linux compilation database. Implicitly or
explicitly constructing std::string() with a "" argument is
inefficient as the caller needs to emit extra instructions to
pass an argument, and the constructor needlessly copies a byte
into internal storage. Rewriting these instances to simply call
the default constructor appears to save ~14-18 kilobytes on an
optimized release build.

BUG=none

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=193020

Review URL: https://codereview.chromium.org/13145003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@193040 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 3 insertions, 3 deletions

diff --git a/chrome/browser/ui/prefs/prefs_tab_helper.cc b/chrome/browser/ui/prefs/prefs_tab_helper.cc
index b629064..7056161 100644
--- a/chrome/browser/ui/prefs/prefs_tab_helper.cc
+++ b/chrome/browser/ui/prefs/prefs_tab_helper.cc
@@ -152,7 +152,7 @@ ALL_FONT_SCRIPTS(WEBKIT_WEBPREFS_FONTS_STANDARD)
       // We haven't already set a default value for this font preference, so set
       // an empty string as the default.
       registry->RegisterStringPref(
-          pref_name, "", PrefRegistrySyncable::UNSYNCABLE_PREF);
+          pref_name, std::string(), PrefRegistrySyncable::UNSYNCABLE_PREF);
     }
   }
 }
@@ -587,7 +587,7 @@ void PrefsTabHelper::RegisterUserPrefs(PrefRegistrySyncable* registry) {
                                         IDS_STATIC_ENCODING_LIST,
                                         PrefRegistrySyncable::UNSYNCABLE_PREF);
   registry->RegisterStringPref(prefs::kRecentlySelectedEncoding,
-                               "",
+                               std::string(),
                                PrefRegistrySyncable::UNSYNCABLE_PREF);
 
   RegisterPrefsToMigrate(registry);
@@ -666,7 +666,7 @@ void PrefsTabHelper::OnWebPrefChanged(const std::string& pref_name) {
     if (pref_value.empty()) {
       WebPreferences web_prefs =
           web_contents_->GetRenderViewHost()->GetWebkitPreferences();
-      OverrideFontFamily(&web_prefs, generic_family, script, "");
+      OverrideFontFamily(&web_prefs, generic_family, script, std::string());
       web_contents_->GetRenderViewHost()->UpdateWebkitPreferences(web_prefs);
       return;
     }