Fix Error object value lookups.

Fix Error object value lookups.

Looking up 'name' and 'message' properties at the same time and loading
the properties later can cause assertion failure if one of the properties
is an accessor and calling it changes the holder map. That may invalidate
the other lookup.

R=jkummerow@chromium.org
BUG=chromium:542101
LOG=N

Committed: https://crrev.com/1a94bc20a12254875704c45262e2b87bf85b63f6
Cr-Commit-Position: refs/heads/master@{#31229}

[Yang, 2015-10-13 08:57:51]

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

[commit-bot: I haz the power, 2015-10-13 08:57:57]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1403923002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1403923002/1

[Jakob Kummerow, 2015-10-13 09:00:52]

lgtm

[commit-bot: I haz the power, 2015-10-13 09:20:30]

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

[commit-bot: I haz the power, 2015-10-13 09:20:31]

Dry run: This issue passed the CQ dry run.

[Yang, 2015-10-13 09:21:21]

The CQ bit was checked by yangguo@chromium.org

[commit-bot: I haz the power, 2015-10-13 09:21:34]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1403923002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1403923002/1

[commit-bot: I haz the power, 2015-10-13 09:26:39]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-13 09:26:55]

Patchset 1 (id:??) landed as
https://crrev.com/1a94bc20a12254875704c45262e2b87bf85b63f6
Cr-Commit-Position: refs/heads/master@{#31229}