Set linux distro to CHROMEOS_RELEASE_DESCRIPTION on ChromeOS

chrome/browser/ui/webui/help/help_handler.cc

Index: chrome/browser/ui/webui/help/help_handler.cc
diff --git a/chrome/browser/ui/webui/help/help_handler.cc b/chrome/browser/ui/webui/help/help_handler.cc
index 10ae5ba6ad940d4c0e6b4d63794378d5bb38333a..7319f0c6d8d69cb0565dacb2e1eeadef09499d8c 100644
--- a/chrome/browser/ui/webui/help/help_handler.cc
+++ b/chrome/browser/ui/webui/help/help_handler.cc
@@ -393,14 +393,14 @@ void HelpHandler::SetPromotionState(VersionUpdater::PromotionState state) {
 
 #if defined(OS_CHROMEOS)
 void HelpHandler::OnOSVersion(chromeos::VersionLoader::Handle handle,
-                              std::string version) {
+                              const std::string& version) {
   scoped_ptr<Value> version_string(Value::CreateStringValue(version));
   web_ui()->CallJavascriptFunction("help.HelpPage.setOSVersion",
                                    *version_string);
 }
 
 void HelpHandler::OnOSFirmware(chromeos::VersionLoader::Handle handle,
-                               std::string firmware) {
+                               const std::string& firmware) {
   scoped_ptr<Value> firmware_string(Value::CreateStringValue(firmware));
   web_ui()->CallJavascriptFunction("help.HelpPage.setOSFirmware",
                                    *firmware_string);