Refactor extension app icon.

chrome/browser/extensions/chrome_app_icon_service.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_EXTENSIONS_CHROME_APP_ICON_SERVICE_H_
+#define CHROME_BROWSER_EXTENSIONS_CHROME_APP_ICON_SERVICE_H_
+
+#include <map>
+#include <memory>
+#include <set>
+
+#include "base/macros.h"
+#include "base/memory/weak_ptr.h"
+#include "base/scoped_observer.h"
+#include "components/keyed_service/core/keyed_service.h"
+#include "extensions/browser/extension_registry_observer.h"
+
+namespace content {
+class BrowserContext;
+}
+
+namespace extensions {
+
+class ChromeAppIcon;
+class ChromeAppIconDelegate;
+
+// Factory for ChromeAppIcon. Each created icon is tracked by this service.
+// Once some condition that affects how extension app icon should look is
+// changed then corresponded app icons are automatically updated. This service
+// is bound to content::BrowserContext.
+// Usage: ChromeAppIconService::Get(context)->CreateIcon().
+class ChromeAppIconService : public KeyedService,
+                             public ExtensionRegistryObserver {
+ public:
+  explicit ChromeAppIconService(content::BrowserContext* context);
+
+  ~ChromeAppIconService() override;
+
+  // Convenience function to get the ChromeAppIconService for a
+  // BrowserContext.
+  static ChromeAppIconService* Get(content::BrowserContext* context);
+
+  // Creates extension app icon for requested app and size. Icon updates are
+  // dispatched via |delegate|.
+  std::unique_ptr<ChromeAppIcon> CreateIcon(ChromeAppIconDelegate* delegate,
+                                            const std::string& app_id,
+                                            int resource_size_in_dip);
+
+  // KeyedService:
+  void Shutdown() override;
+
+ private:
+  class Updater;
+
+  // System may have multiple icons for the same app id with the same of

[msw, 2017/05/10 19:05:21]

nit: "same or" and "dimensions". (or just "multiple icons for the same app id
with different dimensions").

[khmel, 2017/05/11 02:13:48]

Thanks for nice wording.

[khmel, 2017/05/11 02:13:48]

Thanks for nice wording.

+  // different dimension. For example icon in shelf and app launcher.
+  using IconMap = std::map<std::string, std::set<ChromeAppIcon*>>;
+
+  // Called from ChromeAppIcon DTOR.
+  void OnIconDestroyed(ChromeAppIcon* icon);
+
+  // Called from Updater when corresponded app icons need to be updated.
+  void OnAppUpdated(const std::string& app_id);
+
+  // ExtensionRegistryObserver:
+  void OnExtensionLoaded(content::BrowserContext* browser_context,
+                         const Extension* extension) override;
+  void OnExtensionUnloaded(content::BrowserContext* browser_context,
+                           const Extension* extension,
+                           UnloadedExtensionReason reason) override;
+
+  // Unowned pointer.
+  content::BrowserContext* context_;
+
+#if defined(OS_CHROMEOS)
+  // On Chrome OS this handles Chrome app life-cycle events that may change how
+  // extension based app icon looks like.
+  std::unique_ptr<Updater> app_updater_;
+#endif
+
+  IconMap icon_map_;
+
+  ScopedObserver<ExtensionRegistry, ExtensionRegistryObserver> observer_;
+
+  base::WeakPtrFactory<ChromeAppIconService> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(ChromeAppIconService);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_CHROME_APP_ICON_SERVICE_H_