Move DownloadSharedPreferenceEntry handling into another class

chrome/android/java_sources.gni

 # Copyright 2016 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.
 
 chrome_java_sources = [
   "java/src/com/google/android/apps/chrome/appwidget/bookmarks/BookmarkThumbnailWidgetProvider.java",
   "java/src/org/chromium/chrome/browser/ActivityTabTaskDescriptionHelper.java",
   "java/src/org/chromium/chrome/browser/ActivityTaskDescriptionIconGenerator.java",
   "java/src/org/chromium/chrome/browser/AfterStartupTaskUtils.java",
   "java/src/org/chromium/chrome/browser/ApplicationInitialization.java",
@@ skipping 305 matching lines @@
   "java/src/org/chromium/chrome/browser/download/DownloadInfo.java",
   "java/src/org/chromium/chrome/browser/download/DownloadItem.java",
   "java/src/org/chromium/chrome/browser/download/DownloadManagerDelegate.java",
   "java/src/org/chromium/chrome/browser/download/DownloadManagerService.java",
   "java/src/org/chromium/chrome/browser/download/DownloadNotificationService.java",
   "java/src/org/chromium/chrome/browser/download/DownloadNotifier.java",
   "java/src/org/chromium/chrome/browser/download/DownloadPage.java",
   "java/src/org/chromium/chrome/browser/download/DownloadResumptionScheduler.java",
   "java/src/org/chromium/chrome/browser/download/DownloadServiceDelegate.java",
   "java/src/org/chromium/chrome/browser/download/DownloadSharedPreferenceEntry.java",
+  "java/src/org/chromium/chrome/browser/download/DownloadSharedPreferenceHelper.java",
   "java/src/org/chromium/chrome/browser/download/DownloadSnackbarController.java",
   "java/src/org/chromium/chrome/browser/download/DownloadUmaStatsEntry.java",
   "java/src/org/chromium/chrome/browser/download/DownloadUtils.java",
   "java/src/org/chromium/chrome/browser/download/OMADownloadHandler.java",
   "java/src/org/chromium/chrome/browser/download/SystemDownloadNotifier.java",
   "java/src/org/chromium/chrome/browser/download/ui/BackendItems.java",
   "java/src/org/chromium/chrome/browser/download/ui/BackendProvider.java",
   "java/src/org/chromium/chrome/browser/download/ui/DeletedFileTracker.java",
   "java/src/org/chromium/chrome/browser/download/ui/DownloadFilter.java",
   "java/src/org/chromium/chrome/browser/download/ui/DownloadHistoryAdapter.java",
@@ skipping 1230 matching lines @@
   "sync_shell/javatests/src/org/chromium/chrome/browser/sync/SyncTestBase.java",
   "sync_shell/javatests/src/org/chromium/chrome/browser/sync/TypedUrlsTest.java",
   "sync_shell/javatests/src/org/chromium/chrome/browser/sync/ui/PassphraseTypeDialogFragmentTest.java",
 ]
 
 # Only used for testing, should not be shipped to end users.
 if (!is_official_build) {
   chrome_java_sources += [ "java/src/org/chromium/chrome/browser/offlinepages/evaluation/OfflinePageEvaluationBridge.java" ]
   chrome_test_java_sources += [ "javatests/src/org/chromium/chrome/browser/offlinepages/OfflinePageSavePageLaterEvaluationTest.java" ]
 }