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

content/browser/child_process_launcher_helper_posix.cc

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/child_process_launcher_helper_posix.h"
 
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
 #include "base/posix/global_descriptors.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 62 matching lines @@
 
 std::unique_ptr<FileDescriptorInfo> CreateDefaultPosixFilesToMap(
     int child_process_id,
     const mojo::edk::PlatformHandle& mojo_client_handle,
     bool include_service_required_files,
     const std::string& process_type,
     base::CommandLine* command_line) {
   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);
 
   // TODO(jcivelli): remove this "if defined" by making
   // GetAdditionalMappedFilesForChildProcess a no op on Mac.
 #if !defined(OS_MACOSX)
   GetContentClient()->browser()->GetAdditionalMappedFilesForChildProcess(
       *command_line, child_process_id, files_to_register.get());
 #endif
@@ skipping 45 matching lines @@
   DCHECK(GetRequiredFilesByServiceMap().count(service_name) == 0);
   GetRequiredFilesByServiceMap()[service_name] = std::move(required_files);
 }
 
 void ResetFilesToShareForTestingPosix() {
   GetRequiredFilesByServiceMap().clear();
 }
 
 }  // namespace internal
 }  // namespace content