Refactor ZLib and Verbatim encoders.
Refactor ZLib and Verbatim encoders.

Added EncoderRowBased that implements encoding for both ZLib and Verbatim.

BUG=None
TEST=None

Review URL: http://codereview.chromium.org/5382008

git-svn-id: http://src.chromium.org/svn/trunk/src@68384 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 838b5a204ebeedd61e42db0d22ae1fb98d6b9d83
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser