arc-app-launcher: Minimal support for ARC app launcher.

chrome/browser/ui/app_list/arc_app_icon.h

+// Copyright 2015 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_UI_APP_LIST_ARC_APP_ICON_H_
+#define CHROME_BROWSER_UI_APP_LIST_ARC_APP_ICON_H_
+
+#include <string>
+
+#include "base/macros.h"
+#include "base/memory/scoped_vector.h"
+#include "base/memory/weak_ptr.h"
+#include "ui/base/layout.h"
+#include "ui/gfx/image/image.h"
+#include "ui/gfx/image/image_skia.h"
+
+namespace base {
+class FilePath;
+}
+
+namespace content {
+class BrowserContext;
+}
+
+// A class that provides an ImageSkia for UI code to use. It handles Arc app
+// icon resource loading, screen scale factor change etc. UI code that uses
+// Arc app icon should host this class.
+class ArcAppIcon {
+ public:
+  class Observer {
+   public:
+    // Invoked when a new image rep for an additional scale factor
+    // is loaded and added to |image|.
+    virtual void OnIconUpdated() = 0;
+
+   protected:
+    virtual ~Observer() {}
+  };
+
+  ArcAppIcon(content::BrowserContext* context,
+             const std::string& app_id,
+             int resource_size_in_dip,
+             Observer* observer);
+  ~ArcAppIcon();
+
+  gfx::Image image() const { return image_; }
+  const gfx::ImageSkia& image_skia() const { return image_skia_; }
+
+  // Icon loading is performed in several steps. It is initiated by
+  // LoadImageForScaleFactor request that specifies a required scale factor.
+  // ArcAppPrefs is used to resolve a path to resource. Content of file is
+  // asynchronously read in context of browser file thread. On success read,
+  // an icon data is decoded to an image in the special utility process.
+  // DecodeRequest is used to interact with the utility process, and each
+  // active request is stored at decode_requests_ vector. When decoding is
+  // complete, results are returned in context of UI thread, and corresponding
+  // request is removed from decode_requests_. In case of some requests are not
+  // completed by the time of deleting this icon, they are automatically
+  // canceled.
+  // In case of the icon file is not available this requests ArcAppPrefs to
+  // install required resource from Android side. ArcAppPrefs notifies UI items
+  // that new icon is available and corresponding item should invoke
+  // LoadImageForScaleFactor again.
+  void LoadForScaleFactor(ui::ScaleFactor scale_factor);
+
+ private:
+  class Source;
+  class DecodeRequest;
+
+  content::BrowserContext* context_;
+  std::string app_id_;
+  const int resource_size_in_dip_;
+  Observer* observer_;
+
+  Source* source_;  // Owned by ImageSkia storage.
+  gfx::ImageSkia image_skia_;
+
+  // The image wrapper around |image_skia_|.
+  // Note: this is reset each time a new representation is loaded.
+  gfx::Image image_;
+
+  base::WeakPtrFactory<ArcAppIcon> weak_ptr_factory_;

[xiyuan, 2015/11/11 22:15:50]

[chromium-style] WeakPtrFactory members which refer to their outer class must be
the last member in the outer class definition.

[khmel1, 2015/11/12 08:05:29]

Done.

+
+  // Contains pending image decode requests.
+  ScopedVector<DecodeRequest> decode_requests_;
+
+  void RequestIcon(ui::ScaleFactor scale_factor);
+  void ReadOnFileThread(ui::ScaleFactor scale_factor,
+                        const base::FilePath& path);
+  void OnIconRead(ui::ScaleFactor scale_factor,
+                  const std::string& unsafe_image_data);
+  void Update(const gfx::ImageSkia* image);
+  void DiscardDecodeRequest(DecodeRequest* request);

[xiyuan, 2015/11/11 22:15:50]

Methods should precede data members.
See https://google.github.io/styleguide/cppguide.html#Declaration_Order

[khmel1, 2015/11/12 08:05:29]

Done.

+
+  DISALLOW_COPY_AND_ASSIGN(ArcAppIcon);
+};
+
+#endif  // CHROME_BROWSER_UI_APP_LIST_ARC_APP_ICON_H_