Allow native code running in reduced mode to launch full browser

This cl implements NativeStartupBridge which allows native code running
in reduced mode to interface with java and launch full browser. The
first client of this is DownloadService which is being refactored into
being able to run in reduced mode but may require launching full browser
if needed.

Change-Id: I27d2d7cb4a7d89fa376698e7773a6d41b5daf4d3
Reviewed-by: David Trainor <>
Reviewed-by: Steven Holte <>
Commit-Queue: Mohamed Heikal <>
Cr-Commit-Position: refs/heads/master@{#653060}
7 files changed