Use SharedPersistentMemoryAllocator to share field trial state

content/browser/gpu/gpu_process_host.h

 // Copyright (c) 2012 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.
 
 #ifndef CONTENT_BROWSER_GPU_GPU_PROCESS_HOST_H_
 #define CONTENT_BROWSER_GPU_GPU_PROCESS_HOST_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 274 matching lines @@
   // received, assume all of these URLs are guilty, and block
   // automatic execution of 3D content from those domains.
   std::multiset<GURL> urls_with_live_offscreen_contexts_;
 
   typedef std::map<int32_t, scoped_refptr<ShaderDiskCache>>
       ClientIdToShaderCacheMap;
   ClientIdToShaderCacheMap client_id_to_shader_cache_;
 
   std::string shader_prefix_key_;
 
-  // Anonymous shared memory segment to share with subprocess containing list of
-  // field trials (represented as a string).
-  // TODO(crbug.com/653874): Eventually remove this and use single shared memory
-  // object across processes.
-  std::unique_ptr<base::SharedMemory> field_trial_state_;
-
   DISALLOW_COPY_AND_ASSIGN(GpuProcessHost);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_GPU_GPU_PROCESS_HOST_H_