GitLab

(previously 149749).

Again, we use the interface to use the cache when available, or to
load from a temporary file in incognito, when the cache is not available.

Differences from previous try:
* double-fd-close bug.
* compiler warnings that show up in scons build.

BUG= http://code.google.com/p/nativeclient/issues/detail?id=2683

Review URL: https://chromiumcodereview.appspot.com/10834173

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@150093 0039d316-1c4b-4281-b951-d872f2087c98