Convert more automation calls to the JSON interface.

chrome/test/automation/automation_proxy.cc

Index: chrome/test/automation/automation_proxy.cc
diff --git a/chrome/test/automation/automation_proxy.cc b/chrome/test/automation/automation_proxy.cc
index d5f1a60e7eef8c1fed7b632be998446a43c22095..8371d74f1d90be434a2d969712d70787d30a44d8 100644
--- a/chrome/test/automation/automation_proxy.cc
+++ b/chrome/test/automation/automation_proxy.cc
@@ -466,10 +466,6 @@ bool AutomationProxy::EndTracing(std::string* json_trace_output) {
   return true;
 }
 
-bool AutomationProxy::ResetToDefaultTheme() {
-  return Send(new AutomationMsg_ResetToDefaultTheme());
-}
-
 bool AutomationProxy::SendJSONRequest(const std::string& request,
                                       int timeout_ms,
                                       std::string* response) {