Add a class to replace ImageLoadingTracker with a nicer API.

chrome/browser/extensions/image_utils.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_UTILS_H_
+#define CHROME_BROWSER_EXTENSIONS_IMAGE_UTILS_H_
+
+#include <vector>
+
+#include "base/callback_forward.h"
+#include "chrome/common/extensions/extension_resource.h"
+#include "ui/base/layout.h"
+#include "ui/gfx/size.h"
+
+namespace extensions {
+class Extension;
+}
+
+namespace gfx {
+class Image;
+}
+
+namespace extension_image_utils {
+
+void LoadImageAsync(const extensions::Extension* extension,
+                    const ExtensionResource& resource,
+                    const gfx::Size& max_size,
+                    const base::Callback<void(const gfx::Image&)>& callback);
+
+// Information about a singe image representation to load from an extension
+// resource.
+struct ImageRepresentation {
+  // Enum values to indicate whether to resize loaded bitmap when it is larger
+  // than |desired_size| or always resize it.
+  enum ResizeCondition {
+    RESIZE_WHEN_LARGER,
+    ALWAYS_RESIZE,
+  };
+
+  ImageRepresentation(const ExtensionResource& resource,
+                      ResizeCondition resize_condition,
+                      const gfx::Size& desired_size,
+                      ui::ScaleFactor scale_factor);
+  ~ImageRepresentation();
+
+  // Extension resource to load.
+  ExtensionResource resource;
+
+  ResizeCondition resize_condition;
+
+  // When |resize_method| is ALWAYS_RESIZE or when the loaded image is larger
+  // than |desired_size| it will be resized to these dimensions.
+  gfx::Size desired_size;
+
+  // |scale_factor| is used to construct the loaded gfx::ImageSkia.
+  ui::ScaleFactor scale_factor;
+};
+
+void LoadImagesAsync(const extensions::Extension* extension,
+                     const std::vector<ImageRepresentation>& info_list,
+                     const base::Callback<void(const gfx::Image&)>& callback);
+
+}  // namespace extension_image_utils
+
+#endif  // CHROME_BROWSER_EXTENSIONS_IMAGE_UTILS_H_