Return NOT_FOUND error for an attempt to create a file under nonexistent directory.
Return NOT_FOUND error for an attempt to create a file under nonexistent directory.

BUG=none
TEST=fast/filesystem/op-get-entry.html

Review URL: http://codereview.chromium.org/3729001

git-svn-id: http://src.chromium.org/svn/trunk/src@62229 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: ab6c19b2fe985e659a9f64ff4d66aab5db3b101f
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser