Add basic stacktrace handler using libunwind.

gyp/tools.gyp

 # GYP file to build various tools.
 #
 # To build on Linux:
 #  ./gyp_skia tools.gyp && make tools
 #
 {
   'includes': [
     'apptype_console.gypi',
   ],
   'targets': [
@@ skipping 282 matching lines @@
         '../bench/SkBenchLogger.cpp',
         '../tools/bench_pictures_main.cpp',
       ],
       'include_dirs': [
         '../src/core/',
         '../bench',
         '../src/lazy/',
       ],
       'dependencies': [
         'bench.gyp:bench_timer',
+        'crash_handler.gyp:CrashHandler',
         'flags.gyp:flags',
         'jsoncpp.gyp:jsoncpp',
         'skia_lib.gyp:skia_lib',
+        'tools.gyp:picture_renderer',
         'tools.gyp:picture_utils',
-        'tools.gyp:picture_renderer',
         'tools.gyp:timer_data',
       ],
     },
     {
       'target_name': 'bench_record',
       'type': 'executable',
       'sources': [
         '../tools/bench_record.cpp',
         '../tools/LazyDecodeBitmap.cpp',
       ],
@@ skipping 300 matching lines @@
             'type': 'executable',
             'sources': [
               '../tools/win_lcid.cpp',
             ],
           },
         ],
       },
     ],
   ],
 }