Add UMA to measure feasibility of making unique names immutable

content/renderer/render_frame_impl.h

 // Copyright 2013 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_RENDERER_RENDER_FRAME_IMPL_H_
 #define CONTENT_RENDERER_RENDER_FRAME_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 1275 matching lines @@
   mojo::Binding<mojom::Frame> frame_binding_;
   mojom::FrameHostPtr frame_host_;
 
   // Indicates whether |didAccessInitialDocument| was called.
   bool has_accessed_initial_document_;
 
   AssociatedInterfaceRegistryImpl associated_interfaces_;
   std::unique_ptr<AssociatedInterfaceProviderImpl>
       remote_associated_interfaces_;
 
+  // TODO(dcheng): Remove these members.
+  bool committed_first_load_ = false;
+  bool name_changed_before_first_commit_ = false;
+
   base::WeakPtrFactory<RenderFrameImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderFrameImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_RENDER_FRAME_IMPL_H_