Refactor extension app icon.

chrome/browser/extensions/extension_app_icon.h

Index: chrome/browser/extensions/extension_app_icon.h
diff --git a/chrome/browser/extensions/extension_app_icon.h b/chrome/browser/extensions/extension_app_icon.h
new file mode 100644
index 0000000000000000000000000000000000000000..92af64f156c7c43680c9b836a5955d59cd3738bd
--- /dev/null
+++ b/chrome/browser/extensions/extension_app_icon.h
@@ -0,0 +1,81 @@
+// 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_EXTENSION_APP_ICON_H_
+#define CHROME_BROWSER_EXTENSIONS_EXTENSION_APP_ICON_H_
+
+#include <memory>
+#include <string>
+
+#include "base/callback.h"
+#include "base/macros.h"
+#include "extensions/browser/extension_icon_image.h"
+#include "ui/gfx/image/image_skia.h"
+
+namespace content {
+class BrowserContext;
+}
+
+namespace extensions {
+
+class Extension;
+class ExtensionAppIconDelegate;
+class IconImage;
+
+// This represents how an extension icon should finally look. As a base,

[Devlin, 2017/04/26 22:41:57]

This is really only used for app icons, right?  Extension icons (such as those
shown in context menus, the toolbar, the extensions page, etc) are all
different.  We should probably say "app icon" here.

[khmel, 2017/04/27 00:18:12]

Make sense, updated to extension app icon.

+// extension icon is used and effects that depend on extension type, state and
+// some external conditions are applied. Resulting image is sent via
+// ExtensionAppIconDelegate. Several updates are expected in case extension
+// state or some external conditions are changed.
+class ExtensionAppIcon : public extensions::IconImage::Observer {

[Devlin, 2017/04/26 22:41:57]

Similarly, maybe this whole class should just be ChromeAppIcon?

[Devlin, 2017/04/26 22:41:57]

no need for extensions:: prefix inside the extensions namespace (this whole
file)

[khmel, 2017/04/27 00:18:12]

this would cause a confusion with ARC apps which have different loading.

[khmel, 2017/04/27 00:18:12]

Done.

[Devlin, 2017/05/01 14:51:10]

"Chrome Apps" are separate from ARC apps, and I haven't heard or seen references
to ARC/android apps as chrome apps in the code.  On the other hand, extensions
and apps are different, and an "extension app" isn't a thing. :)  Additionally,
given the file location, I think the overlap with ARC is sufficiently low that
differentiating between extensions is more important.  I'm open to alternative
suggestions, but I think "ExtensionApp" is a bit too unusual.

[khmel, 2017/05/01 20:18:18]

Renamed to ChromeAppIcon.

+ public:
+  using DestroyCallback = base::Callback<void(ExtensionAppIcon*)>;

[Devlin, 2017/04/26 22:41:57]

nit: DestroyedCallback, or OnDestroyedCallback.

[Devlin, 2017/04/26 22:41:57]

Can this be a OnceCallback?

[khmel, 2017/04/27 00:18:12]

Done.

[khmel, 2017/04/27 00:18:12]

Done.

+
+  ExtensionAppIcon(ExtensionAppIconDelegate* delegate,
+                   content::BrowserContext* context,
+                   DestroyCallback destroy_callback,
+                   const std::string& app_id,
+                   int resource_size_in_dip);
+  ~ExtensionAppIcon() override;
+
+  void Reload();

[Devlin, 2017/04/26 22:41:57]

Add a function comment

[khmel, 2017/04/27 00:18:12]

Done.

+
+  // Returns true if icon is loaded and attached to valid extension.
+  bool IsValid() const;
+
+  void UpdateIcon();
+
+  void EnsureRepsForSupportedScales();

[Devlin, 2017/04/26 22:41:57]

Add a function comment

[khmel, 2017/04/27 00:18:12]

Done.

+
+  const gfx::ImageSkia& image_skia() const { return image_skia_; }
+  const std::string& app_id() const { return app_id_; }
+  content::BrowserContext* context() { return context_; }
+
+ private:
+  const extensions::Extension* GetExtension();
+
+  // extensions::IconImage::Observer:
+  void OnExtensionIconImageChanged(extensions::IconImage* image) override;
+
+  // Unowned pointers.
+  ExtensionAppIconDelegate* const delegate_;
+  content::BrowserContext* const context_;
+
+  DestroyCallback destroy_callback_;
+
+  const std::string app_id_;
+
+  const int resource_size_in_dip_;
+
+  // Contains current icon image.
+  gfx::ImageSkia image_skia_;
+
+  std::unique_ptr<extensions::IconImage> icon_;
+
+  DISALLOW_COPY_AND_ASSIGN(ExtensionAppIcon);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_APP_ICON_H_