Thanks. It loads quite a few dependencies:

  Loading NaCl module.
  Loaded runnable-ld.so [1057 KiB]
  Loaded emacs_x86_64.nexe [5559 KiB]
  Loaded libppapi_simple.so [390 KiB]
  Loaded libpthread.so.1106743a [1529 KiB]
  Loaded libnacl_io.so [3626 KiB]
  Loaded libppapi_cpp.so [2489 KiB]
  Loaded libstdc++.so.6 [5583 KiB]
  Loaded libtiff.so.5 [659 KiB]
  Loaded libjpeg.so.8 [453 KiB]
  Loaded libpng16.so.16 [466 KiB]
  Loaded libz.so.1 [233 KiB]
  Loaded libm.so.1106743a [1270 KiB]
  Loaded libgif.so.4 [147 KiB]
  Loaded libXaw.so.7 [805 KiB]
  Loaded libXmu.so.6 [255 KiB]
  Loaded libXt.so.6 [773 KiB]
  Loaded libSM.so.6 [147 KiB]
  Loaded libICE.so.6 [244 KiB]
  Loaded libXext.so.6 [232 KiB]
  Loaded libX11.so.6 [1964 KiB]
  Loaded librt.so.1106743a [467 KiB]
  Loaded libncurses.so.5 [595 KiB]
  Loaded libc.so.1106743a [11743 KiB]
  Loaded libgcc_s.so.1 [336 KiB]
  Loaded libXpm.so.4 [222 KiB]
  Loaded libxcb.so.1 [296 KiB]
  Loaded libXau.so.6 [138 KiB]
  Loaded libdl.so.1106743a [314 KiB]
  Unable to create home directory in persistent storage: No such file or directory

At that point I thought it had failed, but after about a minute emacs came up. On OSX it seems to use about 215-240 MB, vs anywhere from 50-200 MB for my other chrome tabs.

Anyone have crouton handy to compare the overhead?