Remove unused functions in V8Collection.h
Remove unused functions in V8Collection.h

Forgot to remove in r148617 and r148356.

R=haraken@chromium.org
BUG=229740
TEST=No tests.

Review URL: https://codereview.chromium.org/13996023

Patch from Koji Hara <kojih@chromium.org>.

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@148989 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