Add a mode flag to the tracing framework.

content/browser/tracing/trace_message_filter.cc

Index: content/browser/tracing/trace_message_filter.cc
diff --git a/content/browser/tracing/trace_message_filter.cc b/content/browser/tracing/trace_message_filter.cc
index de5b2fd93e18d66b7e533236b741c04f7550a82c..a02ac4ec7eb866ab4d85a8dd9f8d51ebef72a54b 100644
--- a/content/browser/tracing/trace_message_filter.cc
+++ b/content/browser/tracing/trace_message_filter.cc
@@ -56,11 +56,14 @@ bool TraceMessageFilter::OnMessageReceived(const IPC::Message& message,
 
 void TraceMessageFilter::SendBeginTracing(
     const std::vector<std::string>& included_categories,
-    const std::vector<std::string>& excluded_categories) {
+    const std::vector<std::string>& excluded_categories,
+    base::debug::TraceLog::TraceMode mode) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  Send(new TracingMsg_BeginTracing(included_categories,
-                                   excluded_categories,
-                                   base::TimeTicks::NowFromSystemTraceTime()));
+  Send(new TracingMsg_BeginTracing(
+      included_categories,
+      excluded_categories,
+      base::TimeTicks::NowFromSystemTraceTime(),
+      base::debug::TraceLog::StringFromTraceMode(mode)));
 }
 
 void TraceMessageFilter::SendEndTracing() {