Revert of Remove post_launch_on_client_thread_called

content/browser/child_process_launcher_helper.h

Index: content/browser/child_process_launcher_helper.h
diff --git a/content/browser/child_process_launcher_helper.h b/content/browser/child_process_launcher_helper.h
index 71329561f18cbef2b6e439d7c1e8fc3c5b1511fd..6c8ed7dcc21f5825645a15b1a2b1d7016c1fb2b1 100644
--- a/content/browser/child_process_launcher_helper.h
+++ b/content/browser/child_process_launcher_helper.h
@@ -122,10 +122,14 @@
       const base::LaunchOptions& options);
 
   // Called once the process has been created, successfully or not.
+  // If |post_launch_on_client_thread_called| is false,
+  // this calls PostLaunchOnClientThread on the client thread.
   void PostLaunchOnLauncherThread(ChildProcessLauncherHelper::Process process,
-                                  int launch_result);
-
-  // Posted by PostLaunchOnLauncherThread onto the client thread.
+                                  int launch_result,
+                                  bool post_launch_on_client_thread_called);
+
+  // Note that this could be called before PostLaunchOnLauncherThread() is
+  // called.
   void PostLaunchOnClientThread(ChildProcessLauncherHelper::Process process,
                                 int error_code);