I've just landed a change that split chrome_tests.gypi into two parts:
chrome_tests_unit.gypi, which has the unit tests and the support targets
needed for unit tests, and chrome_tests.gypi, which has all the other tests
(browser, interactive ui, etc.). If you're looking for unit_tests,
test_support_unit, test_support_common, or a couple of other
unit-test-related targets, they aren't where you last saw them.
This was both to make sharing gypi files with iOS easier (non-unit tests
generally require things that aren't possible on iOS, like forking
processes), and to break up what had become the project's largest gypi file
(at 5k lines and 38 targets).