Correct process id for sandbox'd trace events.

content/browser/zygote_main_linux.cc

Index: content/browser/zygote_main_linux.cc
diff --git a/content/browser/zygote_main_linux.cc b/content/browser/zygote_main_linux.cc
index db8039fb1755963d9db3cf3e75f83e086c3052c4..68ec5e1e8f0cd664bae81ada59cfb5f59f284faa 100644
--- a/content/browser/zygote_main_linux.cc
+++ b/content/browser/zygote_main_linux.cc
@@ -16,6 +16,7 @@
 
 #include "base/basictypes.h"
 #include "base/command_line.h"
+#include "base/debug/trace_event.h"
 #include "base/eintr_wrapper.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
@@ -327,6 +328,10 @@ class Zygote {
       // Sandboxed processes need to send the global, non-namespaced PID when
       // setting up an IPC channel to their parent.
       IPC::Channel::SetGlobalPid(real_pid);
+      // Force the real PID so chrome event data have a PID that corresponds
+      // to system trace event data.
+      base::debug::TraceLog::GetInstance()->SetProcessID(
+          static_cast<int>(real_pid));

[Markus (顧孟勤), 2012/04/20 21:13:29]

You mentioned that this is currently something that is only need for CrOS. Just
double-checking that you verified the code is harmless on non-CrOS builds for
OS_LINUX.

Other than that, this change looks fine to me. Glad to see that it is a
relatively simple and well-contained change. Of course, computing thread ids is
going to be a little more challenging.

 #endif
       close(pipe_fds[0]);
       close(dummy_fd);