Pass the GUID for the SharedMemoryHandle used by base::FieldTrialList.

content/browser/child_process_launcher_helper_posix.cc

Index: content/browser/child_process_launcher_helper_posix.cc
diff --git a/content/browser/child_process_launcher_helper_posix.cc b/content/browser/child_process_launcher_helper_posix.cc
index 96efa993d5158a944547d90ceed3d84e4e49a15d..9b2f6e0fc6285b2453e77974a4e12a4f8bde8ddc 100644
--- a/content/browser/child_process_launcher_helper_posix.cc
+++ b/content/browser/child_process_launcher_helper_posix.cc
@@ -80,9 +80,12 @@ std::unique_ptr<FileDescriptorInfo> CreateDefaultPosixFilesToMap(
   std::unique_ptr<FileDescriptorInfo> files_to_register(
       FileDescriptorInfoImpl::Create());
 
-  int field_trial_handle = base::FieldTrialList::GetFieldTrialHandle();
-  if (field_trial_handle != base::kInvalidPlatformFile)
-    files_to_register->Share(kFieldTrialDescriptor, field_trial_handle);
+  base::SharedMemoryHandle shm = base::FieldTrialList::GetFieldTrialHandle();
+  if (shm.IsValid()) {
+    files_to_register->Share(
+        kFieldTrialDescriptor,
+        base::SharedMemory::GetFdFromSharedMemoryHandle(shm));
+  }
 
   DCHECK(mojo_client_handle.is_valid());
   files_to_register->Share(kMojoIPCChannel, mojo_client_handle.handle);