Expand memoized_unittest and clarify error message.

Expand memoized_unittest and clarify error message.

Specifically:
 - Improve style in memoized_unittest
 - Make test methods clearer
 - Make error message clearer if a non-hashable type is passed to a memoized function
 - Add unit test for this

The purpose of this change is just to clarify the code.

Committed: https://crrev.com/550547d0385f1cb8a905d4322a7ae7452a0d3e7b
Cr-Commit-Position: refs/heads/master@{#401337}

[qyearsley, 2016-06-20 16:48:29]

[email protected] changed reviewers:
+ [email protected]

[Dirk Pranke, 2016-06-21 23:56:11]

lgtm

[qyearsley, 2016-06-22 16:31:33]

The CQ bit was checked by [email protected]

[commit-bot: I haz the power, 2016-06-22 16:32:05]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/2073193003/20001

[commit-bot: I haz the power, 2016-06-22 17:47:19]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-06-22 17:50:55]

Description was changed from

==========
Expand memoized_unittest and clarify error message.

Specifically:
 - Improve style in memoized_unittest
 - Make test methods clearer
 - Make error message clearer if a non-hashable type is passed to a memoized
function
 - Add unit test for this

The purpose of this change is just to clarify the code.
==========

to

==========
Expand memoized_unittest and clarify error message.

Specifically:
 - Improve style in memoized_unittest
 - Make test methods clearer
 - Make error message clearer if a non-hashable type is passed to a memoized
function
 - Add unit test for this

The purpose of this change is just to clarify the code.

Committed: https://crrev.com/550547d0385f1cb8a905d4322a7ae7452a0d3e7b
Cr-Commit-Position: refs/heads/master@{#401337}
==========

[commit-bot: I haz the power, 2016-06-22 17:50:56]

Patchset 2 (id:??) landed as
https://crrev.com/550547d0385f1cb8a905d4322a7ae7452a0d3e7b
Cr-Commit-Position: refs/heads/master@{#401337}