Use SharedPersistentMemoryAllocator to share field trial state

content/browser/renderer_host/render_process_host_impl.h

Index: content/browser/renderer_host/render_process_host_impl.h
diff --git a/content/browser/renderer_host/render_process_host_impl.h b/content/browser/renderer_host/render_process_host_impl.h
index fc3d8c144dd492c8b68297d4266daa71b2cb3633..26795707166d278dcee8a3be0305115ca670fcd6 100644
--- a/content/browser/renderer_host/render_process_host_impl.h
+++ b/content/browser/renderer_host/render_process_host_impl.h
@@ -577,12 +577,6 @@ class CONTENT_EXPORT RenderProcessHostImpl
   // The memory allocator, if any, in which the renderer will write its metrics.
   std::unique_ptr<base::SharedPersistentMemoryAllocator> metrics_allocator_;
 
-  // 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_;
-
   bool channel_connected_;
   bool sent_render_process_ready_;