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

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

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@193020 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 5 insertions, 4 deletions

diff --git a/chrome/browser/managed_mode/managed_user_service.cc b/chrome/browser/managed_mode/managed_user_service.cc
index 0cc29f5..80b2bc8 100644
--- a/chrome/browser/managed_mode/managed_user_service.cc
+++ b/chrome/browser/managed_mode/managed_user_service.cc
@@ -154,10 +154,10 @@ void ManagedUserService::RegisterUserPrefs(PrefRegistrySyncable* registry) {
                                 ManagedModeURLFilter::BLOCK,
                                 PrefRegistrySyncable::UNSYNCABLE_PREF);
   registry->RegisterStringPref(prefs::kManagedModeLocalPassphrase,
-                               "",
+                               std::string(),
                                PrefRegistrySyncable::UNSYNCABLE_PREF);
   registry->RegisterStringPref(prefs::kManagedModeLocalSalt,
-                               "",
+                               std::string(),
                                PrefRegistrySyncable::UNSYNCABLE_PREF);
 }
 
@@ -203,7 +203,7 @@ bool ManagedUserService::UserMayLoad(const extensions::Extension* extension,
                                      string16* error) const {
   string16 tmp_error;
   // |extension| can be NULL in unit tests.
-  if (ExtensionManagementPolicyImpl(extension ? extension->id() : "",
+  if (ExtensionManagementPolicyImpl(extension ? extension->id() : std::string(),
                                     &tmp_error))
     return true;
 
@@ -244,7 +244,8 @@ bool ManagedUserService::UserMayModifySettings(
     const extensions::Extension* extension,
     string16* error) const {
   // |extension| can be NULL in unit tests.
-  return ExtensionManagementPolicyImpl(extension ? extension->id() : "", error);
+  return ExtensionManagementPolicyImpl(
+      extension ? extension->id() : std::string(), error);
 }
 
 void ManagedUserService::Observe(int type,