It looks not goma's problem.

ninja looks not allow space in application name.
https://github.com/ninja-build/ninja/blob/master/src/subprocess-win32.cc#L109
https://msdn.microsoft.com/en-us/library/windows/desktop/ms682425(v=vs.85).aspx

ninja too supports this fine:

C:\src\chrome\src>type foo.cc
#include <stdio.h>
int main() {
  FILE* f = fopen("bar.txt", "wb");
  fprintf(f, "hello\n");
  fclose(f);
}

C:\src\chrome\src>cl /nologo foo.cc
foo.cc

C:\src\chrome\src>type build.ninja
rule gcc
  command = foo bar.exe

build foo.txt: gcc bar.txt


C:\src\chrome\src>type foo.txt
The system cannot find the file specified.

C:\src\chrome\src>ninja
[1/1] foo bar.exe

C:\src\chrome\src>type foo.txt
hello



gn probably doesn't escape this path quite right or something. In any case, doesn't seem super important. Goma likely isn't the only thing not handling spaces in directory names well.

Ninja has the problem. The project won't build at all if it lives in any path with spaces in OSX. Spaces in volume names are perfectly normal in the Mac world. 

[1/1] Regenerating ninja files
FAILED: build.ninja
/Volumes/Mac 2TB/Users/jjimenez/chromium/src/buildtools/mac/gn --root=/Volumes/Mac 2TB/Users/jjimenez/chromium/src -q gen .
/bin/sh: /Volumes/Mac: is a directory
ninja: error: rebuilding 'build.ninja': subcommand failed