Removed O(n!) traversal of selectors for selectorList.
Removed O(n!) traversal of selectors for selectorList.

When collectFeaturesFromSelector got a for-loop for tagHistory in [1], the
for-loop for tagHistory was kept in collectFeaturesFromSelectorList which
means we did n! visits of n sub-selectors in selectors like
:-webkit-any(.a.b.c).

[1] https://codereview.chromium.org/143653010

R=esprehn,chrishtr
BUG=335247

Review URL: https://codereview.chromium.org/172993002

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@167475 bbb929c8-8fbe-4397-9dbb-9b2b20218538

primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs