Update from https://crrev.com/333737

mojo/edk/js/handle.h

 // Copyright 2014 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 MOJO_EDK_JS_HANDLE_H_
 #define MOJO_EDK_JS_HANDLE_H_
 
 #include "base/observer_list.h"
 #include "gin/converter.h"
 #include "gin/handle.h"
@@ skipping 21 matching lines @@
 
   void AddCloseObserver(HandleCloseObserver* observer);
   void RemoveCloseObserver(HandleCloseObserver* observer);
 
  protected:
   HandleWrapper(MojoHandle handle);
   ~HandleWrapper() override;
   void NotifyCloseObservers();
 
   mojo::ScopedHandle handle_;
-  ObserverList<HandleCloseObserver> close_observers_;
+  base::ObserverList<HandleCloseObserver> close_observers_;
 };
 
 }  // namespace js
 }  // namespace mojo
 
 namespace gin {
 
 // Note: It's important to use this converter rather than the one for
 // MojoHandle, since that will do a simple int32 conversion. It's unfortunate
 // there's no way to prevent against accidental use.
@@ skipping 36 matching lines @@
       return false;
     }
     *out = gin::Handle<mojo::js::HandleWrapper>(val, object);
     return true;
   }
 };
 
 }  // namespace gin
 
 #endif  // MOJO_EDK_JS_HANDLE_H_