Don't call hb_buffer_set_unicode_funcs in HarfBuzzShaper

Don't call hb_buffer_set_unicode_funcs in HarfBuzzShaper

Harfbuzz-ng 0.9.27 introduced a HAVE_ICU_BUILTIN define which makes the
hb_buffer_set_unicode_funcs call redundant. Also call
hb_buffer_clear_content instead of hb_buffer_reset which is faster now
that we no longer explicitly set the unicode functions.

BUG=354117
R=dglazkov@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=169604

[dglazkov, 2014-03-19 20:06:19]

lgtm

[eae, 2014-03-19 23:23:26]

The CQ bit was checked by eae@chromium.org

[commit-bot: I haz the power, 2014-03-19 23:23:35]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/eae@chromium.org/197213032/1

[commit-bot: I haz the power, 2014-03-20 00:36:47]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-03-20 00:36:47]

Commit queue rejected this change because the description was changed
between the time the change entered the commit queue and the time it
was ready to commit. You can safely check the commit box again.

[eae, 2014-03-20 00:39:33]

The CQ bit was checked by eae@chromium.org

[commit-bot: I haz the power, 2014-03-20 00:40:14]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/eae@chromium.org/197213032/1

[commit-bot: I haz the power, 2014-03-20 03:49:21]

Change committed as 169604