Update DevTools Tracing.Start to accept trace config as a parameter

content/browser/devtools/protocol/tracing_handler.h

Index: content/browser/devtools/protocol/tracing_handler.h
diff --git a/content/browser/devtools/protocol/tracing_handler.h b/content/browser/devtools/protocol/tracing_handler.h
index 970710b9278add86b003cd6560ead3153b2f4615..b6707e4a60e33135b1906c4e62be73d40beed3f1 100644
--- a/content/browser/devtools/protocol/tracing_handler.h
+++ b/content/browser/devtools/protocol/tracing_handler.h
@@ -51,7 +51,8 @@ class TracingHandler {
                  const std::string* categories,
                  const std::string* options,
                  const double* buffer_usage_reporting_interval,
-                 const std::string* transfer_mode);
+                 const std::string* transfer_mode,
+                 const scoped_ptr<base::DictionaryValue>& config);
   Response End(DevToolsCommandId command_id);
   Response GetCategories(DevToolsCommandId command);
   Response RequestMemoryDump(DevToolsCommandId command_id);