country_names.cc: SetLocaleString takes const ref

SetLocaleString took a string by value and used std::move on it.

After a discussion on chromium-dev [1], pasing a const ref was recognised as
the preferred style in Chromium, so this CL changes it.

[1]
https://groups.google.com/a/chromium.org/forum/#!searchin/chromium-dev/string$20const$20ref/chromium-dev/ZoAfW7GXUVI/fCYjkg2JBAAJ

BUG=571610
R=isherman@chromium.org

Review URL: https://codereview.chromium.org/1635813003

Cr-Commit-Position: refs/heads/master@{#371617}

components/autofill/core/browser/country_names.cc

@@ -5,7 +5,6 @@
 #include "components/autofill/core/browser/country_names.h"
 
 #include <stdint.h>
-#include <utility>
 
 #include "base/lazy_instance.h"
 #include "base/logging.h"
@@ -142,13 +141,13 @@ CountryNames* CountryNames::GetInstance() {
 }
 
 // static
-void CountryNames::SetLocaleString(std::string locale) {
+void CountryNames::SetLocaleString(const std::string& locale) {
   DCHECK(!locale.empty());
   // Application locale should never be empty. The empty value of
   // |g_application_locale| means that it has not been initialized yet.
   std::string* storage = g_application_locale.Pointer();
   if (storage->empty()) {
-    *storage = std::move(locale);
+    *storage = locale;
   }
   // TODO(crbug.com/579971) CountryNames currently cannot adapt to changed
   // locale without Chrome's restart.

components/autofill/core/browser/country_names.h

@@ -33,7 +33,7 @@ class CountryNames {
   // Tells CountryNames, what is the application locale. Only the first supplied
   // value is used, further calls result in no changes.  Call this on the UI
   // thread, before first using CountryNames. |locale| must not be empty.
-  static void SetLocaleString(std::string locale);
+  static void SetLocaleString(const std::string& locale);
 
   // Returns the country code corresponding to |country|, which should be a
   // country code or country name localized to |locale_name|.