Add missing #include related to sequenced_worker_pool.h to android files

This is an android related part of https://codereview.chromium.org/2690533002/ PS6.

These files depends on indirectly-included sequnced_worker_pool.h, which
is being removed.

[email protected], [email protected], [email protected]

Review-Url: https://codereview.chromium.org/2694713005
Cr-Commit-Position: refs/heads/master@{#450633}
diff --git a/chrome/browser/android/shortcut_helper.cc b/chrome/browser/android/shortcut_helper.cc
index dfa0aefc..aa309f6 100644
--- a/chrome/browser/android/shortcut_helper.cc
+++ b/chrome/browser/android/shortcut_helper.cc
@@ -15,6 +15,7 @@
 #include "base/command_line.h"
 #include "base/strings/string16.h"
 #include "base/strings/utf_string_conversions.h"
+#include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/android/webapk/chrome_webapk_host.h"
 #include "chrome/browser/android/webapk/webapk_install_service.h"
 #include "chrome/browser/manifest/manifest_icon_downloader.h"