Continue conversion to more properties.
Continue conversion to more properties.

Make Dependency.file_list a tuple so it can't be modified.
Move the guesswork of file_list at the right place.
Remove tree() since it's unnecessary.

R=dpranke@chromium.org
BUG=
TEST=all smoke tests still pass


Review URL: http://codereview.chromium.org/7922011

git-svn-id: bd64dd6fa6f3f0ed0c0666d1018379882b742947@101951 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

svn2github/chromium-depot-tools,svn2github/chromium-depot-tools,svn2github/chromium-depot-tools