crash_reporter: Remove Chrome collector, CrOS build files, DBus

Removed the ChromeOS specific code so that the code compiles.  The code
removed is not needed when running on Android, and includes:
* Chrome collector
* ChromeOS build's gyp file
* ChromeOS-specific DBus calls
* ChromeOS-specific collector path logic
* Chrome bypass logic in user collector

Bug: 22672752
Change-Id: I3c7d87c971a181d8f73293519318e3602d142927