Cleanup: Pass std::string as const reference if possible

ui/accessibility/ax_node_data.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/accessibility/ax_node_data.h"
 
 #include <set>
 
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
@@ skipping 226 matching lines @@
 void AXNodeData::AddBoolAttribute(
     AXBoolAttribute attribute, bool value) {
   bool_attributes.push_back(std::make_pair(attribute, value));
 }
 
 void AXNodeData::AddIntListAttribute(
     AXIntListAttribute attribute, const std::vector<int32>& value) {
   intlist_attributes.push_back(std::make_pair(attribute, value));
 }
 
-void AXNodeData::SetName(std::string name) {
+void AXNodeData::SetName(const std::string& name) {
   string_attributes.push_back(std::make_pair(AX_ATTR_NAME, name));
 }
 
-void AXNodeData::SetValue(std::string value) {
+void AXNodeData::SetValue(const std::string& value) {
   string_attributes.push_back(std::make_pair(AX_ATTR_VALUE, value));
 }
 
 std::string AXNodeData::ToString() const {
   std::string result;
 
   result += "id=" + IntToString(id);
   result += " " + ui::ToString(role);
 
   if (state & (1 << AX_STATE_BUSY))
@@ skipping 414 matching lines @@
 bool AXNodeData::IsRoot() const {
   return (role == AX_ROLE_ROOT_WEB_AREA ||
           role == AX_ROLE_DESKTOP);
 }
 
 void AXNodeData::SetRoot() {
   role = AX_ROLE_ROOT_WEB_AREA;
 }
 
 }  // namespace ui