Re-land "Add ability to check /etc/lsb-release for HWID"

This reverts commit 33ab35b140d9d0da49d971cad26fb2f1b52215b0.


Add ability to check /etc/lsb-release for HWID

This is enabled by a compile-time option, only.

On certain boards HWID may not be available via normal means.
This functionality allows a compile-time choice to enable
behavior that will check /etc/lsb-release for an
HWID_OVERRIDE=<id> entry instead.

CQ-DEPEND=CL:186482
BUG=None
TEST=unit tests

Change-Id: I75a7bcf7219fbb19670647746735c814dacf7879
Reviewed-on: https://chromium-review.googlesource.com/187040
Reviewed-by: Chris Sosa <sosa@chromium.org>
Commit-Queue: Chris Masone <cmasone@chromium.org>
Tested-by: Chris Masone <cmasone@chromium.org>
diff --git a/extent_writer_unittest.cc b/extent_writer_unittest.cc
index f0f5f7a..55cbff6 100644
--- a/extent_writer_unittest.cc
+++ b/extent_writer_unittest.cc
@@ -40,7 +40,7 @@
   }
   int fd() { return fd_; }
   const char* path() { return path_; }
-  
+
   // Writes data to an extent writer in 'chunk_size' chunks with
   // the first chunk of size first_chunk_size. It calculates what the
   // resultant file should look like and ensure that the extent writer