Make object.h usable without object-inl.h header.

Make object.h usable without object-inl.h header.

This CL us a pure refactoring that makes an empty compilation unit
including just "object.h" but not "object-inl.h" compile without
warnings or errors. This is needed to further reduce the header
dependency tangle.

R=bmeurer@chromium.org

Committed: https://crrev.com/40c11d060c13885263338645990c22aab23f197d
Cr-Commit-Position: refs/heads/master@{#30152}

[Benedikt Meurer, 2015-08-13 11:05:51]

LGTM (rubberstamped)

[Michael Starzinger, 2015-08-13 11:24:56]

The CQ bit was checked by mstarzinger@chromium.org

[Michael Starzinger, 2015-08-13 11:24:56]

The patchset sent to the CQ was uploaded after l-g-t-m from bmeurer@chromium.org
Link to the patchset: https://codereview.chromium.org/1286403002/#ps20001
(title: "Fix typo.")

[commit-bot: I haz the power, 2015-08-13 11:24:59]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1286403002/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1286403002/20001

[commit-bot: I haz the power, 2015-08-13 11:49:06]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-08-13 11:49:16]

Patchset 2 (id:??) landed as
https://crrev.com/40c11d060c13885263338645990c22aab23f197d
Cr-Commit-Position: refs/heads/master@{#30152}