Link against sandbox_static.lib

* vendor/libchromiumcontent 15ada44...c973a7c (3):
  > Create and export sandbox_static.lib for Windows clients
  > Export content/app/startup_helper_win.cc to clients
  > Rename dist/include to dist/src

brightray/brightray.gyp

@@ -74,6 +74,7 @@
           'link_settings': {
             'libraries': [
               '<(libchromiumcontent_library_dir)/chromiumcontent.dll.lib',
+              '<(libchromiumcontent_library_dir)/sandbox_static.lib',
             ],
           },
         }],