CC: Add 'cc-benchmark' traces for minimal tracing in benchmarks.

ipc/ipc_message.h

Index: ipc/ipc_message.h
diff --git a/ipc/ipc_message.h b/ipc/ipc_message.h
index 17cbd2469cc9c53734928b52ce9a013ebc3d0068..6fe43156e593d1479ccd720e2bfba3bb2210b176 100644
--- a/ipc/ipc_message.h
+++ b/ipc/ipc_message.h
@@ -217,12 +217,12 @@ class IPC_EXPORT Message : public Pickle {
 
   // Called to trace when message is sent.
   void TraceMessageBegin() {
-    TRACE_EVENT_FLOW_BEGIN0(TRACE_DISABLED_BY_DEFAULT("toplevel.flow"), "IPC",
+    TRACE_EVENT_FLOW_BEGIN0(TRACE_DISABLED_BY_DEFAULT("task.flow"), "IPC",
         header()->flags);
   }
   // Called to trace when message is received.
   void TraceMessageEnd() {
-    TRACE_EVENT_FLOW_END0(TRACE_DISABLED_BY_DEFAULT("toplevel.flow"), "IPC",
+    TRACE_EVENT_FLOW_END0(TRACE_DISABLED_BY_DEFAULT("task.flow"), "IPC",
         header()->flags);
   }