chromeos: Fix pixelated icons in app list and launcher (part 2) (by xiyuan)

chrome/browser/extensions/extension_icon_image.h

+// Copyright (c) 2012 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_ICON_IMAGE_H_
+#define CHROME_BROWSER_EXTENSIONS_EXTENSION_ICON_IMAGE_H_
+
+#include <map>
+#include <string>
+
+#include "base/basictypes.h"
+#include "chrome/browser/extensions/image_loading_tracker.h"
+#include "chrome/common/extensions/extension_icon_set.h"
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+#include "ui/gfx/image/image_skia.h"
+
+namespace extensions {
+class Extension;
+}
+
+namespace gfx {
+class Size;
+}
+
+namespace extensions {
+
+// A class that provides an ImageSkia for UI code to use. It handles extension
+// icon resource loading, screen scale factor change etc. UI code that uses
+// extension icon should host this class and be its delegate. ExtensionIconImage
+// should be outlived by the delegate. In painting code, UI code paints with the
+// ImageSkia provided by this class. If required extension icon resource is not
+// present, this class uses ImageLoadingTracker to load it and call on its
+// delegate interface when the resource is loaded.
+class IconImage : public ImageLoadingTracker::Observer,
+                  public content::NotificationObserver {
+ public:
+  class Delegate {

[oshima, 2012/08/07 07:43:05]

This should probably called Observer instead of Delegate. Delegate is used when
you need to defer certain operations to others to complete your task.
I'd leave it to OWNERS tho.

[tbarzic, 2012/08/07 18:10:26]

Done.

+   public:
+    // Invoked when |image| is updated with image reps for additional scale
+    // factors.

[oshima, 2012/08/07 07:43:05]

How about
// Invoked when a new image reps for additional scale factors
// is loaded and added to |image|.

[tbarzic, 2012/08/07 18:10:26]

Done.

+    virtual void OnExtensionIconImageChanged(IconImage* image) = 0;
+
+   protected:
+    virtual ~Delegate() {}
+  };
+
+  IconImage(const Extension* extension,
+            const ExtensionIconSet& icon_set,
+            int resource_size_in_dip,
+            ExtensionIconSet::MatchType resource_match_type,
+            const gfx::Size& desired_size_in_dip,
+            ImageLoadingTracker::CacheParam cache_param,
+            Delegate* delegate);
+  virtual ~IconImage();
+
+  const gfx::ImageSkia& image_skia() const { return image_skia_; }
+
+ private:
+  class Source;
+  typedef std::map<int, ui::ScaleFactor> LoadMap;
+
+  // Loads bitmap for additional scale factor.
+  void LoadImageForScaleFactor(ui::ScaleFactor scale_factor);
+
+  // ImageLoadingTracker::Observer overrides:
+  virtual void OnImageLoaded(const gfx::Image& image,
+                             const std::string& extension_id,
+                             int index) OVERRIDE;
+
+  // content::NotificationObserver overrides:
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
+  const Extension* extension_;
+  const ExtensionIconSet& icon_set_;
+  const int resource_size_in_dip_;
+  const ExtensionIconSet::MatchType resource_match_type_;
+  const gfx::Size desired_size_in_dip_;
+  const ImageLoadingTracker::CacheParam cache_param_;
+
+  Delegate* delegate_;
+
+  Source* source_;  // Owned by ImageSkia storage.
+  gfx::ImageSkia image_skia_;
+
+  ImageLoadingTracker tracker_;
+  content::NotificationRegistrar registrar_;
+
+  LoadMap load_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(IconImage);
+};
+
+}  // namespace extensions
+
+#endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_ICON_IMAGE_H_