SkRecord: clean up comments and 4 bytes per SkRecord.

SkRecord: clean up comments and 4 bytes per SkRecord.

Just happened to notice these while skimming through.  The comments are a
little out of date; now that we have visit/mutate, we do need O(1) random
access.

The constructor arguments are flexibility we're not using.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/db26a1267d57f6d8ef5b2fbdeb519be718fc1760

[mtklein_skia, 2014-09-15 19:39:49]

mtklein@skia.org changed reviewers:
+ fmalita@google.com

[mtklein_skia, 2014-09-15 19:39:55]

The CQ bit was checked by mtklein@skia.org

[commit-bot: I haz the power, 2014-09-15 19:40:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/569373002/1

[commit-bot: I haz the power, 2014-09-15 19:40:55]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from a valid reviewer till 2014-09-16 01:40 UTC

[mtklein_skia, 2014-09-15 19:43:32]

The CQ bit was checked by mtklein@skia.org

[commit-bot: I haz the power, 2014-09-15 19:43:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/569373002/20001

[commit-bot: I haz the power, 2014-09-15 19:43:33]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from a valid reviewer till 2014-09-16 01:43 UTC

[commit-bot: I haz the power, 2014-09-15 19:46:52]

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

[commit-bot: I haz the power, 2014-09-15 19:46:53]

Try jobs failed on following builders:
  Test-Ubuntu13.10-GCE-NoGPU-x86_64-Debug-Trybot on tryserver.skia
(http://108.170.220.120:10117/builders/Test-Ubuntu13.10-GCE-NoGPU-x86_64-Debug...)

[mtklein_skia, 2014-09-15 19:49:26]

The CQ bit was checked by mtklein@skia.org

[commit-bot: I haz the power, 2014-09-15 19:49:53]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/569373002/40001

[commit-bot: I haz the power, 2014-09-15 19:49:56]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from a valid reviewer till 2014-09-16 01:49 UTC

[f(malita), 2014-09-15 21:26:36]

fmalita@chromium.org changed reviewers:
+ fmalita@chromium.org

[f(malita), 2014-09-15 21:26:36]

lgtm

[commit-bot: I haz the power, 2014-09-15 21:27:06]

Committed patchset #3 (id:40001) as db26a1267d57f6d8ef5b2fbdeb519be718fc1760