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

ui/accessibility/ax_node_data.h

Index: ui/accessibility/ax_node_data.h
diff --git a/ui/accessibility/ax_node_data.h b/ui/accessibility/ax_node_data.h
index 528b27b71325244727fc720639088614cc4d5cc2..9b517b16b50304527e251181f16c9243dfd7b6d4 100644
--- a/ui/accessibility/ax_node_data.h
+++ b/ui/accessibility/ax_node_data.h
@@ -82,9 +82,9 @@ struct AX_EXPORT AXNodeData {
 
   // Convenience functions, mainly for writing unit tests.
   // Equivalent to AddStringAttribute(ATTR_NAME, name).
-  void SetName(std::string name);
+  void SetName(const std::string& name);
   // Equivalent to AddStringAttribute(ATTR_VALUE, value).
-  void SetValue(std::string value);
+  void SetValue(const std::string& value);
 
   // Return a string representation of this data, for debugging.
   virtual std::string ToString() const;