Revert of Gamma correction for distance field text.

Revert of Gamma correction for distance field text. (https://codereview.chromium.org/258883002/)

Reason for revert:
Memory leaks. I suspect this is due to the lack of destructors in SkAutoGlyphCache

Original issue's description:
> Gamma correction for distance field text.
> 
> Handles both non-LCD and LCD text. Uses a texture to look up the gamma correction values for a given text color or luminance.
> 
> BUG=skia:
> 
> Committed: https://skia.googlesource.com/skia/+/4d517fdbb145cb95e5e935470df331e1b6667cfc

NOTRY=true
NOTREECHECKS=true

Committed: https://skia.googlesource.com/skia/+/919ed4c73633e92bfc6694161360c5c3f45728e8

[scroggo, 2014-06-09 20:01:47]

Created Revert of Gamma correction for distance field text.

[commit-bot: I haz the power, 2014-06-09 20:02:24]

CQ is trying da patch. Follow status at
 https://skia-tree-status.appspot.com/cq/scroggo@google.com/323513005/1

[commit-bot: I haz the power, 2014-06-09 20:02:25]

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

[commit-bot: I haz the power, 2014-06-09 20:02:25]

No LGTM from a valid reviewer yet. Only full committers are accepted.
Even if an LGTM may have been provided, it was from a non-committer or
a provisional committer, _not_ a full super star committer.
See http://www.chromium.org/getting-involved/become-a-committer
Note that this has nothing to do with OWNERS files.

[mtklein, 2014-06-09 20:03:52]

lgtm

[mtklein, 2014-06-09 20:06:04]

The CQ bit was unchecked by mtklein@google.com

[mtklein, 2014-06-09 20:06:10]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2014-06-09 20:06:16]

CQ is trying da patch. Follow status at
 https://skia-tree-status.appspot.com/cq/scroggo@google.com/323513005/1

[commit-bot: I haz the power, 2014-06-09 20:06:39]

Change committed as 919ed4c73633e92bfc6694161360c5c3f45728e8

[scroggo, 2014-06-09 20:09:06]

On 2014/06/09 20:06:39, I haz the power (commit-bot) wrote:
> Change committed as 919ed4c73633e92bfc6694161360c5c3f45728e8

For future reference, there was no TBR etc, making the revert doomed to fail,
because the original CL was over 14 days old. See
https://code.google.com/p/skia/issues/detail?id=2587 (and feel free to complain
in the thread. I don't think this behavior helps anyone)