Implement a new flow event API that allows binding flow events and regular events.

ipc/ipc_channel_reader.cc

Index: ipc/ipc_channel_reader.cc
diff --git a/ipc/ipc_channel_reader.cc b/ipc/ipc_channel_reader.cc
index f41a0d7737e4656cd279db0de8ef83c2b9e9fbaa..4627463d9e50ccb02e3c0f6c8407bd608a76651c 100644
--- a/ipc/ipc_channel_reader.cc
+++ b/ipc/ipc_channel_reader.cc
@@ -82,12 +82,13 @@ bool ChannelReader::DispatchInputData(const char* input_data,
 #ifdef IPC_MESSAGE_LOG_ENABLED
       std::string name;
       Logging::GetInstance()->GetMessageText(m.type(), &name, &m, NULL);
-      TRACE_EVENT1("ipc,toplevel", "ChannelReader::DispatchInputData",
-                   "name", name);
+      TRACE_EVENT_WITH_FLOW1("ipc,toplevel", "ChannelReader::DispatchInputData",
+                             m.flags(), TRACE_EVENT_FLAG_FLOW_IN, "name", name);
 #else
-      TRACE_EVENT2("ipc,toplevel", "ChannelReader::DispatchInputData",
-                   "class", IPC_MESSAGE_ID_CLASS(m.type()),
-                   "line", IPC_MESSAGE_ID_LINE(m.type()));
+      TRACE_EVENT_WITH_FLOW2("ipc,toplevel", "ChannelReader::DispatchInputData",
+                             m.flags(), TRACE_EVENT_FLAG_FLOW_IN, "class",
+                             IPC_MESSAGE_ID_CLASS(m.type()), "line",
+                             IPC_MESSAGE_ID_LINE(m.type()));
 #endif
       m.TraceMessageEnd();
       if (IsInternalMessage(m))