Adds back lookup of 'all' targets
Adds back lookup of 'all' targets

I'm going to add support for 'all'. This is a precursor to that. This
patch effectively adds back code that was removed here:
https://codereview.chromium.org/1402813002 . The code isn't wired up
yet. Will do that next.

TEST=none
BUG=552146
R=mark@chromium.org

Review URL: https://codereview.chromium.org/1438433004 .

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