Remove extension-to-component migration mechanism

chrome/browser/ui/toolbar/component_action_delegate.h

+// Copyright 2017 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 CHROME_BROWSER_UI_TOOLBAR_COMPONENT_ACTION_DELEGATE_H_
+#define CHROME_BROWSER_UI_TOOLBAR_COMPONENT_ACTION_DELEGATE_H_
+
+#include <string>
+
+// Manages component actions in the toolbar model.
+class ComponentActionDelegate {
+ public:
+  virtual ~ComponentActionDelegate() {}
+
+  // Adds or removes the component action labeled by |action_id| from the
+  // toolbar model. The caller must not add the same action twice.
+  virtual void AddComponentAction(const std::string& action_id) = 0;
+  virtual void RemoveComponentAction(const std::string& action_id) = 0;
+
+  // Returns |true| if the toolbar model has an action for |action_id|.
+  virtual bool HasComponentAction(const std::string& action_id) const = 0;
+};
+
+#endif  // CHROME_BROWSER_UI_TOOLBAR_COMPONENT_ACTION_DELEGATE_H_