Cache JumpList icons to avoid unnecessary creation and deletion

chrome/browser/win/jumplist_file_util.h

 // Copyright (c) 2017 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_WIN_JUMPLIST_FILE_UTIL_H_
 #define CHROME_BROWSER_WIN_JUMPLIST_FILE_UTIL_H_
 
+#include "base/containers/flat_set.h"
 #include "base/files/file_path.h"
 
 // Maximum number of icon files allowed to delete per jumplist update.
 const int kFileDeleteLimit = 30;
 
 // This method is similar to base::DeleteFileRecursive in
 // file_util_win.cc with the following differences.
 // 1) It has an input parameter |max_file_deleted| to specify the maximum files
 //    allowed to delete as well as the maximum attempt failures allowd per run.
 // 2) It deletes only the files in |path|. All subdirectories in |path| are
@@ skipping 14 matching lines @@
 // This method firstly calls DeleteDirectoryContent() to delete the contents in
 // |path|. If |path| is empty after the call, it is removed.
 void DeleteDirectory(const base::FilePath& path, int max_file_deleted);
 
 // Deletes the content in the folder at |path| and records the runtime to UMA.
 // TODO(chengx): Remove this method and use DeleteDirectoryContent after fixing
 // http://crbug.com/40407.
 void DeleteDirectoryContentAndLogRuntime(const base::FilePath& path,
                                          int max_file_deleted);
 
+// Returns true if the directory at |path| has more than |max_files| files.
+// Sub-directories are not taken into account here.
+bool FilesExceedLimitInDir(const base::FilePath& path, int max_files);
+
+// Deletes all files in the directory at |path| but not in set |cached_files|.
+void DeleteNonCachedFiles(const base::FilePath& path,
+                          const base::flat_set<base::FilePath>& cached_files);
+
 #endif  // CHROME_BROWSER_WIN_JUMPLIST_FILE_UTIL_H_