Marking M55, RBS as per bug report.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4b442abfbfcd93afdd00d7dd106e71bddbaf19ac

commit 4b442abfbfcd93afdd00d7dd106e71bddbaf19ac
Author: dfalcantara <dfalcantara@chromium.org>
Date: Tue Oct 04 00:24:49 2016

[Downloads] Open media downloads internally

* Force the Custom Tab Intent to use the same package as Chrome
  when opening the media viewer.

* Open media downloads inside of the internal media viewer when
  opening the file in the notification or via the snackbar.

* Shuffle code around for creating media viewer Intents in the
  hopes of consolidating them in places that makes sense.

BUG= 650448 

Review-Url: https://codereview.chromium.org/2376893006
Cr-Commit-Position: refs/heads/master@{#422624}

[modify] https://crrev.com/4b442abfbfcd93afdd00d7dd106e71bddbaf19ac/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadBroadcastReceiver.java
[modify] https://crrev.com/4b442abfbfcd93afdd00d7dd106e71bddbaf19ac/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadManagerService.java
[modify] https://crrev.com/4b442abfbfcd93afdd00d7dd106e71bddbaf19ac/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadNotificationService.java
[modify] https://crrev.com/4b442abfbfcd93afdd00d7dd106e71bddbaf19ac/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadSnackbarController.java
[modify] https://crrev.com/4b442abfbfcd93afdd00d7dd106e71bddbaf19ac/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadUtils.java
[modify] https://crrev.com/4b442abfbfcd93afdd00d7dd106e71bddbaf19ac/chrome/android/java/src/org/chromium/chrome/browser/download/SystemDownloadNotifier.java
[modify] https://crrev.com/4b442abfbfcd93afdd00d7dd106e71bddbaf19ac/chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadFilter.java
[modify] https://crrev.com/4b442abfbfcd93afdd00d7dd106e71bddbaf19ac/chrome/android/java/src/org/chromium/chrome/browser/download/ui/DownloadHistoryItemWrapper.java
[modify] https://crrev.com/4b442abfbfcd93afdd00d7dd106e71bddbaf19ac/chrome/android/javatests/src/org/chromium/chrome/browser/download/DownloadManagerServiceTest.java
[modify] https://crrev.com/4b442abfbfcd93afdd00d7dd106e71bddbaf19ac/chrome/android/javatests/src/org/chromium/chrome/browser/download/DownloadNotificationServiceTest.java
[modify] https://crrev.com/4b442abfbfcd93afdd00d7dd106e71bddbaf19ac/chrome/browser/android/download/download_manager_service.cc

Verified in M55-55.0.2880.3 build

[Auto-generated comment by a script] We noticed that this issue is targeted for M-55; it appears the fix may have landed after branch point, meaning a merge might be required. Please confirm if a merge is required here - if so add Merge-Request-55 label, otherwise remove Merge-TBD label. Thanks.