[Android O] Initialize channels on first launch/upgrade

chrome/android/java_sources.gni

Index: chrome/android/java_sources.gni
diff --git a/chrome/android/java_sources.gni b/chrome/android/java_sources.gni
index 8d9dd54c1a9e7ebcc4314ad9223ccfc8de73ddfc..b7017e87e76d5cd43594568f1333f280cf3278c6 100644
--- a/chrome/android/java_sources.gni
+++ b/chrome/android/java_sources.gni
@@ -564,6 +564,7 @@ chrome_java_sources = [
   "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/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",
@@ -1638,6 +1639,7 @@ chrome_junit_test_java_sources = [
   "junit/src/org/chromium/chrome/browser/media/ui/MediaNotificationButtonComputationTest.java",
   "junit/src/org/chromium/chrome/browser/metrics/VariationsSessionTest.java",
   "junit/src/org/chromium/chrome/browser/notifications/ChannelsInitializerTest.java",
+  "junit/src/org/chromium/chrome/browser/notifications/ChannelsUpdaterTest.java",
   "junit/src/org/chromium/chrome/browser/notifications/NotificationPlatformBridgeUnitTest.java",
   "junit/src/org/chromium/chrome/browser/ntp/NativePageFactoryTest.java",
   "junit/src/org/chromium/chrome/browser/ntp/TitleUtilTest.java",