Break out manifest icon logic from ShortcutHelper

chrome/browser/android/manifest_icon_selector.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_ANDROID_MANIFEST_ICON_SELECTOR_H_
+#define CHROME_BROWSER_ANDROID_MANIFEST_ICON_SELECTOR_H_
+
+#include "base/basictypes.h"
+#include "content/public/common/manifest.h"
+#include "url/gurl.h"
+
+namespace content {
+class WebContents;
+}  // namespace content
+
+namespace IPC {
+class Message;
+}  // namespace IPC
+
+namespace gfx {
+class Screen;
+}
+
+// Selects the icon most closely matching the size constraints.  This follows
+// very basic heuristics -- improvements are welcome.
+class ManifestIconSelector {
+ public:
+  // Runs the algorithm to find the best matching icon in the icons listed in
+  // the Manifest.
+  //
+  // Size is defined in Android's density-independent pixels (dp):
+  // http://developer.android.com/guide/practices/screens_support.html
+  // If/when this class is generalized, it may be a good idea to switch this to
+  // taking in pixels, instead.
+  //
+  // Returns the icon url if a suitable icon is found. An empty URL otherwise.
+  static GURL FindBestMatchingIcon(
+      const std::vector<content::Manifest::Icon>& icons,
+      float preferred_icon_size_in_dp,
+      const gfx::Screen* screen);
+
+ private:
+  explicit ManifestIconSelector(float preferred_icon_size_in_pixels);
+  virtual ~ManifestIconSelector() {}
+
+  // Runs the algorithm to find the best matching icon in the icons listed in
+  // the Manifest.
+  // Returns the icon url if a suitable icon is found. An empty URL otherwise.
+  GURL FindBestMatchingIcon(
+      const std::vector<content::Manifest::Icon>& icons,
+      float density);
+
+  // Runs an algorithm only based on icon declared sizes. It will try to find
+  // size that is the closest to preferred_icon_size_in_pixels_ but bigger than
+  // preferred_icon_size_in_pixels_ if possible.
+  // Returns the icon url if a suitable icon is found. An empty URL otherwise.
+  GURL FindBestMatchingIconForDensity(
+      const std::vector<content::Manifest::Icon>& icons,
+      float density);
+
+  // Returns whether the |preferred_icon_size_in_pixels_| is in |sizes|.
+  bool IconSizesContainsPreferredSize(const std::vector<gfx::Size>& sizes);
+
+  // Returns an array containing the items in |icons| without the unsupported
+  // image MIME types.
+  static std::vector<content::Manifest::Icon> FilterIconsByType(
+      const std::vector<content::Manifest::Icon>& icons);
+
+  // Returns whether the 'any' (ie. gfx::Size(0,0)) is in |sizes|.
+  static bool IconSizesContainsAny(const std::vector<gfx::Size>& sizes);
+
+  const int preferred_icon_size_in_pixels_;
+
+  friend class ManifestIconSelectorTest;
+
+  DISALLOW_COPY_AND_ASSIGN(ManifestIconSelector);
+};
+
+#endif  // CHROME_BROWSER_ANDROID_MANIFEST_ICON_SELECTOR_H_