gyp: cache conditional ASTs for 3 CPU seconds (5%) gain. 

This is in the parallel part so net gain is somewhere between 
5/core_count% and 5%. In chromium on my computer I save roughly 
1.5 seconds in total runtime. 

BUG=chromium:362075
R=mark@chromium.org

Review URL: https://codereview.chromium.org/232773004/
Patch from Daniel Bratell <bratell@opera.com>!


git-svn-id: http://gyp.googlecode.com/svn/trunk@1900 78cadc50-ecff-11dd-a971-7dbc132099af
1 file changed