[Android O] Refactor channel definitions into new 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/AppIndexingUtil.java",
@@ skipping 547 matching lines @@
   "java/src/org/chromium/chrome/browser/metrics/WebappUma.java",
   "java/src/org/chromium/chrome/browser/mojo/ChromeInterfaceRegistrar.java",
   "java/src/org/chromium/chrome/browser/multiwindow/MultiInstanceChromeTabbedActivity.java",
   "java/src/org/chromium/chrome/browser/multiwindow/MultiWindowUtils.java",
   "java/src/org/chromium/chrome/browser/net/qualityprovider/ExternalEstimateProviderAndroid.java",
   "java/src/org/chromium/chrome/browser/net/spdyproxy/DataReductionProxySettings.java",
   "java/src/org/chromium/chrome/browser/nfc/BeamCallback.java",
   "java/src/org/chromium/chrome/browser/nfc/BeamController.java",
   "java/src/org/chromium/chrome/browser/nfc/BeamProvider.java",
   "java/src/org/chromium/chrome/browser/notifications/ActionInfo.java",
+  "java/src/org/chromium/chrome/browser/notifications/ChannelDefinitions.java",
   "java/src/org/chromium/chrome/browser/notifications/ChannelsInitializer.java",
   "java/src/org/chromium/chrome/browser/notifications/ChannelsUpdater.java",
   "java/src/org/chromium/chrome/browser/notifications/ChromeNotificationBuilder.java",
   "java/src/org/chromium/chrome/browser/notifications/CustomNotificationBuilder.java",
   "java/src/org/chromium/chrome/browser/notifications/NotificationBuilder.java",
   "java/src/org/chromium/chrome/browser/notifications/NotificationBuilderBase.java",
   "java/src/org/chromium/chrome/browser/notifications/NotificationBuilderFactory.java",
   "java/src/org/chromium/chrome/browser/notifications/NotificationBuilderForO.java",
   "java/src/org/chromium/chrome/browser/notifications/NotificationCompatBuilder.java",
   "java/src/org/chromium/chrome/browser/notifications/NotificationConstants.java",
@@ skipping 1143 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" ]
 }