Revert "Kill CFX_GrowOnlyPool."

This reverts commit 090d683489bfa3f36f1e2624c310ff9ca5836038.

Symbol appears in files that are not compiled anywhere, it would seem.
Reverting to remove these first.

TBR=thestig@chromium.org

Review URL: https://codereview.chromium.org/1001023003
2 files changed