Refactored loading of applications / extensions icons.

chrome/browser/extensions/image_loader.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_IMAGE_LOADER_H_
 #define CHROME_BROWSER_EXTENSIONS_IMAGE_LOADER_H_
 
 #include <set>
 
 #include "base/callback_forward.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/weak_ptr.h"
+#include "chrome/common/cancelable_task_tracker.h"
 #include "components/browser_context_keyed_service/browser_context_keyed_service.h"
 #include "extensions/common/extension_resource.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 #include "ui/base/layout.h"
 #include "ui/gfx/size.h"
 
+class GURL;
 class Profile;
 
+namespace base {
+class RefCountedMemory;
+}
+
+namespace chrome {
+struct FaviconBitmapResult;
+}
+
 namespace gfx {
 class Image;
 }
 
 namespace extensions {
 
 class Extension;
 
 // This class is responsible for asynchronously loading extension images and
 // calling a callback when an image is loaded.
@@ skipping 30 matching lines @@
     // |scale_factor| is used to construct the loaded gfx::ImageSkia.
     ui::ScaleFactor scale_factor;
   };
 
   struct LoadResult;
 
   // Returns the instance for the given profile, or NULL if none. This is
   // a convenience wrapper around ImageLoaderFactory::GetForProfile.
   static ImageLoader* Get(Profile* profile);
 
-  ImageLoader();
-  virtual ~ImageLoader();
-
   // Checks whether image is a component extension resource. Returns false
   // if a given |resource| does not have a corresponding image in bundled
   // resources. Otherwise fills |resource_id|. This doesn't check if the
   // extension the resource is in is actually a component extension.
   static bool IsComponentExtensionResource(
       const base::FilePath& extension_path,
       const base::FilePath& resource_path,
       int* resource_id);
 
+  // Converts a bitmap image to a PNG representation.
+  static scoped_refptr<base::RefCountedMemory> BitmapToMemory(
+      const SkBitmap* image);
+
+  explicit ImageLoader(Profile* profile);
+  virtual ~ImageLoader();
+
   // Specify image resource to load. If the loaded image is larger than
   // |max_size| it will be resized to those dimensions. IMPORTANT NOTE: this
   // function may call back your callback synchronously (ie before it returns)
   // if the image was found in the cache.
   // Note this method loads a raw bitmap from the resource. All sizes given are
   // assumed to be in pixels.
   void LoadImageAsync(const extensions::Extension* extension,
                       const ExtensionResource& resource,
                       const gfx::Size& max_size,
                       const base::Callback<void(const gfx::Image&)>& callback);
 
   // Same as LoadImage() above except it loads multiple images from the same
   // extension. This is used to load multiple resolutions of the same image
   // type.
   void LoadImagesAsync(const extensions::Extension* extension,
                        const std::vector<ImageRepresentation>& info_list,
-                       const base::Callback<void(const gfx::Image&)>& callback);
+                       const base::Callback<void(const gfx::Image&)>&
+                       callback);
+
+  // Load the icon of the given |extension|. The size in pixels of the returned

[Finnur, 2013/10/02 09:52:15]

nit: Add to the first sentence: and return it via |callback| as a gfx::Image.

[dvh-g, 2013/10/02 15:08:13]

Done.

+  // icon can be chosen with |icon_size|. The icon can also be converted to

[Finnur, 2013/10/02 09:52:15]

Can be? Looks to me like it must be chosen. Unless you can pass in 0x0 or
something, but that should then be documented.

[dvh-g, 2013/10/02 15:08:13]

Done.

+  // grayscale if |grayscale| is set to true. This function will call the
+  // callback with the resulting icon as parameter.
+  void LoadExtensionIconAsync(const extensions::Extension* extension,
+                              int icon_size,
+                              bool grayscale,
+                              const base::Callback<void(const gfx::Image&)>&
+                                  callback);
+
+  // Same as LoadExtensionIconAsync() above except the result icon is returned
+  // as a PNG image data URL.
+  void LoadExtensionIconDataURLAsync(const extensions::Extension* extension,
+                                     int icon_size,
+                                     bool grayscale,
+                                     const base::Callback<void(const GURL&)>&
+                                         callback);
 
  private:
   base::WeakPtrFactory<ImageLoader> weak_ptr_factory_;
 
+  Profile* profile_;
+
+  // Task tracker when getting favicon.
+  CancelableTaskTracker cancelable_task_tracker_;
+
+  // Cache for the default app icon.
+  scoped_ptr<SkBitmap> default_app_icon_;
+
+  // Cache for the default extension icon.
+  scoped_ptr<SkBitmap> default_extension_icon_;
+
   static void LoadImagesOnBlockingPool(
       const std::vector<ImageRepresentation>& info_list,
       const std::vector<SkBitmap>& bitmaps,
       std::vector<LoadResult>* load_result);
 
   void ReplyBack(
       const std::vector<LoadResult>* load_result,
       const base::Callback<void(const gfx::Image&)>& callback);
+
+  // The sequence for LoadExtensionIconAsync() is the following:
+  // 1) It loads the icon image using LoadImageAsync().
+  // 2) When it finishes, LoadExtensionIconLoaded() will be called.
+  // 3) On success, it will call FinalizeImage(). If it failed, it will call
+  // LoadIconFailed(). See below for more on those methods.
+  void LoadExtensionIconDone(const extensions::Extension* extension,
+                             int icon_size,
+                             bool grayscale,
+                             const base::Callback<void(const gfx::Image&)>&
+                             callback,
+                             const gfx::Image& image);
+
+  // Called when the extension doesn't have an icon. We fall back to multiple
+  // sources, using the following order:
+  //  1) The icons as listed in the extension manifests.
+  //  2) If a 16px icon and the extension has a launch URL, see if Chrome has a
+  //  corresponding favicon.
+  //  3) If still no matches, load the default extension icon.
+  void LoadIconFailed(const extensions::Extension* extension,
+                      int icon_size,
+                      bool grayscale,
+                      const base::Callback<void(const gfx::Image&)>& callback);
+
+  // Loads the favicon image for the given |extension|. If the image does not
+  // exist, we fall back to the default image.
+  void LoadFaviconImage(const extensions::Extension* extension,
+                        int icon_size,
+                        bool grayscale,
+                        const base::Callback<void(const gfx::Image&)>&
+                        callback);
+
+  // FaviconService callback. It will call FinalizedImage() on success or try
+  // another fallback.
+  void OnFaviconDataAvailable(
+      const extensions::Extension* extension,
+      int icon_size,
+      bool grayscale,
+      const base::Callback<void(const gfx::Image&)>& callback,
+      const chrome::FaviconBitmapResult& bitmap_result);
+
+  // The sequence for LoadDefaultImage() will be the following:
+  // 1) LoadDefaultImage() will invoke LoadDefaultImageOnFileThread() on the
+  // file thread.
+  // 2) LoadDefaultImageOnFileThread() will perform the work, then invoke
+  // LoadDefaultImageDone() on the UI thread.
+  void LoadDefaultImage(const extensions::Extension* extension,
+                        int icon_size,
+                        bool grayscale,
+                        const base::Callback<void(const gfx::Image&)>&
+                            callback);
+
+  // Loads the default image on the file thread.
+  void LoadDefaultImageOnFileThread(
+      const extensions::Extension* extension,
+      int icon_size,
+      bool grayscale,
+      const base::Callback<void(const gfx::Image&)>& callback);
+
+  // When loading of default image is done, it will call FinalizeImage().
+  void LoadDefaultImageDone(const gfx::Image& image,
+                            bool grayscale,
+                            const base::Callback<void(const gfx::Image&)>&
+                                callback);
+
+  // Performs any remaining transformations (like desaturating the |image|),
+  // then returns the |image| to the |callback|.
+  //
+  // The sequence for FinalizeImage() will be the following:
+  // 1) FinalizeImage() will invoke FinalizeImageOnFileThread() on the file
+  // thread.
+  // 2) FinalizeImageOnFileThread() will perform the work, then invoke
+  // FinalizeImageDone() on the UI thread.
+  void FinalizeImage(const gfx::Image& image,
+                     bool grayscale,
+                     const base::Callback<void(const gfx::Image&)>& callback);
+
+  // Process the "finalize" operation on the file thread.
+  void FinalizeImageOnFileThread(const gfx::Image& image,
+                                 bool grayscale,
+                                 const base::Callback<void(const gfx::Image&)>&
+                                 callback);
+
+  // Called when the "finalize" operation on the file thread is done.
+  void FinalizeImageDone(const gfx::Image& image,
+                         const base::Callback<void(const gfx::Image&)> &
+                         callback);
+
+  // The sequence for LoadExtensionIconDataURLAsync() will be the following:
+  // 1) Call LoadExtensionIconAsync() to fetch the icon of the extension.
+  // 2) When the icon is loaded, OnIconAvailable() will be called and will
+  // invoke ConvertIconToURLOnFileThread() on the file thread.
+  // 3) OnIconConvertedToURL() will be called on the UI thread when it's done
+  // and will call the callback.
+  //
+  // LoadExtensionIconDataURLAsync() will use LoadExtensionIconAsync() to get
+  // the icon of the extension. The following method will be called when the
+  // image has been fetched.
+  void OnIconAvailable(const base::Callback<void(const GURL&)>& callback,
+                       const gfx::Image& image);
+
+  // ConvertIconToURLOnFileThread() will convert the image to a PNG image data
+  // URL on the file thread.
+  void ConvertIconToURLOnFileThread(const gfx::Image& image,
+                                    const base::Callback<void(const GURL&)>&
+                                    callback);
+
+  // This method will call the callback of LoadExtensionIconDataURLAsync() with
+  // the result.
+  void OnIconConvertedToURL(const GURL& url,
+                            const base::Callback<void(const GURL&)>& callback);
+
+  // Returns the bitmap for the default extension icon.
+  const SkBitmap* GetDefaultExtensionImage();
+
+  // Returns the bitmap for the default app icon.
+  const SkBitmap* GetDefaultAppImage();
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_IMAGE_LOADER_H_