Revert "app_shell: Add experimental shellPrivate extension API"

extensions/browser/api/shell_private/shell_private_api.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 EXTENSIONS_BROWSER_API_SHELL_PRIVATE_SHELL_PRIVATE_API_H_
-#define EXTENSIONS_BROWSER_API_SHELL_PRIVATE_SHELL_PRIVATE_API_H_
-
-#include "base/macros.h"
-#include "extensions/browser/extension_function.h"
-
-namespace extensions {
-
-// Synchronously prints "hello" to the console.
-class ShellPrivatePrintHelloFunction : public UIThreadExtensionFunction {
- public:
-  DECLARE_EXTENSION_FUNCTION("shellPrivate.printHello", UNKNOWN);
-
-  ShellPrivatePrintHelloFunction();
-
- protected:
-  virtual ~ShellPrivatePrintHelloFunction();
-
-  // ExtensionFunction:
-  virtual ResponseAction Run() override;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(ShellPrivatePrintHelloFunction);
-};
-
-}  // namespace extensions
-
-#endif  // EXTENSIONS_BROWSER_API_SHELL_PRIVATE_SHELL_PRIVATE_API_H_