Avoid implicit size_t conversions on setting HeapObjectHeader::m_encoded.

Avoid implicit size_t conversions on setting HeapObjectHeader::m_encoded.

Cannot assume that sizeof(size_t) matches that of uint32_t.

R=
BUG=

Committed: https://crrev.com/89e2fb3f209cea22b85819b078e98b92725d148b
Cr-Commit-Position: refs/heads/master@{#360703}

[sof, 2015-11-19 16:06:25]

sigbjornf@opera.com changed reviewers:
+ oilpan-reviews@chromium.org

[sof, 2015-11-19 16:06:26]

please take a look.

cf. compile failures on win64 bot --


http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Win%20x64%20Bui...

[haraken, 2015-11-19 23:16:40]

LGTM

[haraken, 2015-11-19 23:16:46]

The CQ bit was checked by haraken@chromium.org

[commit-bot: I haz the power, 2015-11-19 23:19:46]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1459933002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1459933002/1

[commit-bot: I haz the power, 2015-11-20 01:19:17]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-20 01:20:24]

Patchset 1 (id:??) landed as
https://crrev.com/89e2fb3f209cea22b85819b078e98b92725d148b
Cr-Commit-Position: refs/heads/master@{#360703}