Pure pedantry: Replace all ".size() == 0" with ".empty()".

chrome/browser/password_manager/password_store_mac.cc

Index: chrome/browser/password_manager/password_store_mac.cc
diff --git a/chrome/browser/password_manager/password_store_mac.cc b/chrome/browser/password_manager/password_store_mac.cc
index abdb9c73032b1aaf299c5d9cd9695c9d8e254149..f53d1deb187cf31364dad8b65e9fab3f56a8c18a 100644
--- a/chrome/browser/password_manager/password_store_mac.cc
+++ b/chrome/browser/password_manager/password_store_mac.cc
@@ -451,7 +451,7 @@ std::vector<PasswordForm*> GetPasswordsForForms(
     std::vector<PasswordForm*> keychain_matches =
         keychain_adapter.PasswordsMergeableWithForm(**i);
     MergePasswordForms(&keychain_matches, &db_form_container, &merged_forms);
-    if (db_form_container.size() == 0) {
+    if (db_form_container.empty()) {
       i = database_forms->erase(i);
     } else {
       ++i;
@@ -626,7 +626,7 @@ SecKeychainItemRef MacKeychainPasswordFormAdapter::KeychainItemForForm(
   std::vector<SecKeychainItemRef> matches = MatchingKeychainItems(
       form.signon_realm, form.scheme, path.c_str(), username.c_str());
 
-  if (matches.size() == 0) {
+  if (matches.empty()) {
     return NULL;
   }
   // Free all items after the first, since we won't be returning them.