Use SharedPersistentMemoryAllocator to share field trial state

content/browser/child_process_launcher.h

Index: content/browser/child_process_launcher.h
diff --git a/content/browser/child_process_launcher.h b/content/browser/child_process_launcher.h
index 943aba2e1ab89ce640824e2e142e989a06e3086d..71c33faa4f4fe004d65bd61cfe70d01e8dacee5e 100644
--- a/content/browser/child_process_launcher.h
+++ b/content/browser/child_process_launcher.h
@@ -80,7 +80,6 @@ class CONTENT_EXPORT ChildProcessLauncher : public base::NonThreadSafe {
       base::CommandLine* cmd_line,
       int child_process_id,
       Client* client,
-      const base::SharedMemory* field_trial_state,
       const std::string& mojo_child_token,
       const mojo::edk::ProcessErrorCallback& process_error_callback,
       bool terminate_on_shutdown = true);
@@ -118,8 +117,7 @@ class CONTENT_EXPORT ChildProcessLauncher : public base::NonThreadSafe {
   // Posts a task to the launcher thread to do the actual work.
   void Launch(SandboxedProcessLauncherDelegate* delegate,
               base::CommandLine* cmd_line,
-              int child_process_id,
-              const base::SharedMemory* field_trial_state);
+              int child_process_id);
 
   void UpdateTerminationStatus(bool known_dead);