Refactor barcode decoder to use Zxing's C++ version

By using the C++ version of Zxing, we can avoid having Java and Ant
as a dependency when running Video quality analysis on the bots.
This makes it far more easy to setup automation on new machines.

I also moved the scripts into the webrtc/ folder so it will be synced by default when building in Chrome (eliminating the need of a separate solution).

This CL also removes the need of the FFMPEG_HOME variable and replaces
its use with a command line flag to make the tool run smoothly on
Windows.

BUG=none
TEST=locally running the script on Windows, Mac and Linux.

Review URL: https://webrtc-codereview.appspot.com/1099007

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@3640 4adac7df-926f-26a2-2b94-8c16560cd09d
7 files changed