Implement Encoding API

Implement Encoding API

Initial implementation, behind the experimental features flag.

Tests are derived from my JS impl: code.google.com/p/stringencoding/

Many of the tests have FAIL results, due to a mix of:
* Mismatch between canonical encoding names
* Unsupported encodings from the spec
* Extra encodings (e.g "us-ascii") that are mapped differently in the spec
* Issues with streaming encode/decode (e.g. split UTF-16 code units)
* Possible encoder differences

In other words, there's still a lot of work to do.

BUG=243354
R=dglazkov@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=155379

[jsbell, 2013-07-16 22:05:22]

Might be worth landing this now just so it doesn't get moldy again, but
otherwise there's no rush.

[Ken Russell (switch to Gerrit), 2013-07-18 19:32:42]

LGTM. The tests look great, and thorough. A plan is needed to finish the
implementation and enable it by default.

[Ken Russell (switch to Gerrit), 2013-07-30 22:31:55]

Is there any reason not to commit this? If not, let's do it!

[jsbell, 2013-07-30 22:43:04]

On 2013/07/30 22:31:55, Ken Russell wrote:
> Is there any reason not to commit this? If not, let's do it!

FWIW, I was on vacation last week and am out next week as well, so it won't get
much of my attention. Also, it would make sense for the two of us (kbr, jsbell)
to be OWNERS in Source/modules/encoding if that's acceptable.

Otherwise, just waiting on a LGTM from a Source/modules owner.

[dglazkov, 2013-07-31 20:06:14]

lgtm

[commit-bot: I haz the power, 2013-07-31 20:13:33]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jsbell@chromium.org/15901002/11001

[commit-bot: I haz the power, 2013-07-31 21:49:34]

Retried try job too often on linux_blink_rel for step(s) webkit_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_blin...

[commit-bot: I haz the power, 2013-07-31 22:09:53]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jsbell@chromium.org/15901002/11001

[commit-bot: I haz the power, 2013-08-01 00:32:18]

Retried try job too often on linux_blink_rel for step(s) webkit_tests
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_blin...

[commit-bot: I haz the power, 2013-08-01 20:49:38]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/jsbell@chromium.org/15901002/36001

[commit-bot: I haz the power, 2013-08-02 04:31:32]

Change committed as 155379