Refactor extension app icon.

chrome/browser/extensions/chrome_app_icon_loader.h

+// Copyright 2016 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_EXTENSIONS_CHROME_APP_ICON_LOADER_H_
+#define CHROME_BROWSER_EXTENSIONS_CHROME_APP_ICON_LOADER_H_
+
+#include <map>
+#include <memory>
+#include <string>
+
+#include "base/macros.h"
+#include "chrome/browser/extensions/chrome_app_icon_delegate.h"
+#include "chrome/browser/ui/app_icon_loader.h"
+
+class Profile;
+
+namespace extensions {
+
+// Implementation of AppIconLoader that uses ChromeAppIcon to load and update
+// Chrome app images.
+class ChromeAppIconLoader : public AppIconLoader, public ChromeAppIconDelegate {
+ public:
+  ChromeAppIconLoader(Profile* profile,
+                      int icon_size_in_dips,
+                      AppIconLoaderDelegate* delegate);
+  ~ChromeAppIconLoader() override;
+
+  // AppIconLoader overrides:
+  bool CanLoadImageForApp(const std::string& id) override;
+  void FetchImage(const std::string& id) override;
+  void ClearImage(const std::string& id) override;
+  void UpdateImage(const std::string& id) override;
+
+ private:
+  using ExtensionIDToChromeAppIconMap =
+      std::map<std::string, std::unique_ptr<ChromeAppIcon>>;
+
+  // ChromeAppIconDelegate:
+  void OnIconUpdated(ChromeAppIcon* icon) override;
+
+  // Maps from extension id to ChromeAppIcon.
+  ExtensionIDToChromeAppIconMap map_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChromeAppIconLoader);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_CHROME_APP_ICON_LOADER_H_