Merge the 2019-01-01 SPL branch from AOSP-Partner

* security-aosp-nyc-mr2-release:
  AOSP/Email - Fixed - Security Vulnerability - Email App: Malicious app is able to compose message with hidden attachments and bypass attachments path checks attaching private files from /data/data/com.android.email/*

Change-Id: I97751da451a3a778dd521e22f6f35e3702fa8e19