Add SK_BEGIN_REQUIRE_DENSE / SK_END_REQUIRE_DENSE.

Add SK_BEGIN_REQUIRE_DENSE / SK_END_REQUIRE_DENSE.

Use in on a few examples of things we hash.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/b68ce74bd197a9ca4becd53cbcfee825b8d08e0e

[mtklein, 2015-11-20 18:28:50]

The CQ bit was checked by mtklein@google.com to run a CQ dry run

[commit-bot: I haz the power, 2015-11-20 18:28:54]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1468483002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1468483002/20001

[mtklein, 2015-11-20 18:29:01]

Description was changed from

==========
Add SK_BEGIN_REQUIRE_DENSE / SK_END_REQUIRE_DENSE.

Use it in a few example places.

BUG=skia:
==========

to

==========
Add SK_BEGIN_REQUIRE_DENSE / SK_END_REQUIRE_DENSE.

Use in on a few examples of things we hash.

BUG=skia:
==========

[commit-bot: I haz the power, 2015-11-20 18:29:47]

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

[commit-bot: I haz the power, 2015-11-20 18:29:47]

Dry run: Try jobs failed on following builders:
  Build-Ubuntu-GCC-Arm7-Debug-Android-Trybot on client.skia.compile (JOB_FAILED,
http://build.chromium.org/p/client.skia.compile/builders/Build-Ubuntu-GCC-Arm...)
  Build-Ubuntu-GCC-Mips-Debug-Android-Trybot on client.skia.compile (JOB_FAILED,
http://build.chromium.org/p/client.skia.compile/builders/Build-Ubuntu-GCC-Mip...)
  Build-Ubuntu-GCC-x86_64-Release-Trybot on client.skia.compile (JOB_FAILED,
http://build.chromium.org/p/client.skia.compile/builders/Build-Ubuntu-GCC-x86...)

[mtklein, 2015-11-20 19:42:42]

The CQ bit was checked by mtklein@google.com to run a CQ dry run

[commit-bot: I haz the power, 2015-11-20 19:42:54]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1468483002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1468483002/40001

[commit-bot: I haz the power, 2015-11-20 21:32:32]

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

[commit-bot: I haz the power, 2015-11-20 21:32:33]

Dry run: This issue passed the CQ dry run.

[mtklein_C, 2015-11-23 16:53:39]

mtklein@chromium.org changed reviewers:
+ reed@google.com
- mtklein@google.com

[mtklein_C, 2015-11-23 16:53:40]

Follow up to the CL from last week about tweaking struct layouts.

[mtklein_C, 2015-11-23 16:55:29]

The CQ bit was checked by mtklein@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-11-23 16:55:36]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1468483002/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1468483002/60001

[commit-bot: I haz the power, 2015-11-23 17:07:56]

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

[commit-bot: I haz the power, 2015-11-23 17:07:56]

Dry run: This issue passed the CQ dry run.

[reed1, 2015-11-23 20:05:41]

lgtm

I wonder if we should consider comments or some other way to motivate *why* we
are marking these structs as DENSE... Is there an IS_DENSE(*this) test, that we
could inject in our code in the places where we rely on this (e.g. right before
we try to hash the struct)?

[mtklein, 2015-11-23 20:07:27]

> Is there an IS_DENSE(*this) test, that we could inject in our code in the
places where we rely on this (e.g. right before we try to hash the struct)?

Nope.  I wish there were, so I could write this as a single
static_assert<IS_DENSE(T), ""> instead of BEGIN...END.

[mtklein, 2015-11-23 23:00:36]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-11-23 23:00:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1468483002/60001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1468483002/60001

[commit-bot: I haz the power, 2015-11-24 13:36:01]

Committed patchset #4 (id:60001) as
https://skia.googlesource.com/skia/+/b68ce74bd197a9ca4becd53cbcfee825b8d08e0e