LargeIconService returns icon of the desired size

components/favicon/core/large_icon_service.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 COMPONENTS_FAVICON_CORE_LARGE_ICON_SERVICE_H_
 #define COMPONENTS_FAVICON_CORE_LARGE_ICON_SERVICE_H_
 
 #include <vector>
 
 #include "base/macros.h"
@@ skipping 20 matching lines @@
 // the favicon service.
 class LargeIconService : public KeyedService {
  public:
   LargeIconService(
       FaviconService* favicon_service,
       const scoped_refptr<base::TaskRunner>& background_task_runner,
       std::unique_ptr<image_fetcher::ImageFetcher> image_fetcher);
   ~LargeIconService() override;
 
   // Requests the best large icon for the page at |page_url|.
-  // Case 1. An icon exists whose size is >= |min_source_size_in_pixel|:
+  // Case 1. An icon exists whose size is >= MAX(|min_source_size_in_pixel|,
+  // |desired_size_in_pixel|):
   // - If |desired_size_in_pixel| == 0: returns icon as is.
   // - Else: returns the icon resized to |desired_size_in_pixel|.
-  // Case 2. An icon exists whose size is < |min_source_size_in_pixel|:
+  // Case 2. An icon exists whose size is >= |min_source_size_in_pixel| and <
+  // |desired_size_in_pixel|:
+  // - Same as 1 with the biggest icon.
+  // Case 4. An icon exists whose size is < |min_source_size_in_pixel|:

[jkrcal, 2017/05/18 12:33:55]

Where is Case 3?

   // - Extracts dominant color of smaller image, returns a fallback icon style
   //   that has a matching background.
-  // Case 3. No icon exists.
+  // Case 5. No icon exists.
   // - Returns the default fallback icon style.
-  // For cases 2 and 3, this function returns the style of the fallback icon
+  // For cases 4 and 5, this function returns the style of the fallback icon
   // instead of rendering an icon so clients can render the icon themselves.
   // TODO(jkrcal): Rename to GetLargeIconRawBitmapOrFallbackStyle.
   base::CancelableTaskTracker::TaskId GetLargeIconOrFallbackStyle(
       const GURL& page_url,
       int min_source_size_in_pixel,
       int desired_size_in_pixel,
       const favicon_base::LargeIconCallback& callback,
       base::CancelableTaskTracker* tracker);
 
   // Behaves the same as GetLargeIconOrFallbackStyle(), only returns the large
@@ skipping 48 matching lines @@
   std::vector<int> large_icon_types_;
 
   std::unique_ptr<image_fetcher::ImageFetcher> image_fetcher_;
 
   DISALLOW_COPY_AND_ASSIGN(LargeIconService);
 };
 
 }  // namespace favicon
 
 #endif  // COMPONENTS_FAVICON_CORE_LARGE_ICON_SERVICE_H_