Add --properties for things like gitHash that describe the current nanobench run.

gyp/bench.gyp

 # GYP file to build performance testbench.
 #
 {
   'includes': [
     'apptype_console.gypi',
   ],
   'targets': [
     {
       'target_name': 'nanobench',
       'type': 'executable',
       'sources': [
         '../gm/gm.cpp',
         '../bench/GMBench.cpp',
         '../bench/SKPBench.cpp',
-        '../bench/ResultsWriter.cpp',
         '../bench/nanobench.cpp',
       ],
       'includes': [
         'bench.gypi',
         'gmslides.gypi',
       ],
       'dependencies': [
         'flags.gyp:flags_common',
         'jsoncpp.gyp:jsoncpp',
         'skia_lib.gyp:skia_lib',
         'tools.gyp:crash_handler',
         'tools.gyp:proc_stats',
         'tools.gyp:timer',
       ],
     },
   ],
 }