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;
+}
+
+class ExtensionIconImageDelegate;
+
+// 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. 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.

[tbarzic, 2012/07/25 19:37:34]

pkotwicz 2012/07/25 02:00:39
Can you comment about the expected delegate lifetime here too?
It seems as if we are assuming that the delegate will outline
ExtensionIconImage

[tbarzic, 2012/07/25 19:53:53]

Done.

+class ExtensionIconImage : public ImageLoadingTracker::Observer,
+                           public content::NotificationObserver {
+ public:
+  ExtensionIconImage(const extensions::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,
+                     ExtensionIconImageDelegate* delegate);
+  virtual ~ExtensionIconImage();
+
+  bool IsEmpty() const { return image_skia_.empty(); }

[tbarzic, 2012/07/25 19:37:34]

pkotwicz 2012/07/25 02:00:39
Can you change the name here to IsNull() and check |image_skia_|.isNull(). I
think it's slightly clearer.
The only time IsNull()/IsEmpty() would be true is when no images can be loaded.
(This does not imply that the images have actually been loaded) Can you add a
comment to this effect.)

[tbarzic, 2012/07/25 19:53:53]

Done.

+
+  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 extensions::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_;
+
+  ExtensionIconImageDelegate* delegate_;
+
+  Source* source_;  // Owned by ImageSkia storage.
+  gfx::ImageSkia image_skia_;
+
+  ImageLoadingTracker tracker_;
+  content::NotificationRegistrar registrar_;
+
+  LoadMap load_map_;
+
+  DISALLOW_COPY_AND_ASSIGN(ExtensionIconImage);
+};
+
+#endif  // CHROME_BROWSER_EXTENSIONS_EXTENSION_ICON_IMAGE_H_