bookmarks: Enable running BookmarkEditorView unit tests on Linux.

bookmarks: Enable running BookmarkEditorView unit tests on Linux.

Previously it was running only on Windows, but due to migration to Aura,
we should be running it on Linux as well.

This makes the necessary changes to get it running on Linux.

BUG=None
TEST=unit_tests --gtest_filter=BookmarkEditor*
R=sky@chromium.org

Committed: https://crrev.com/5631bd75102560b6ba31a809fe319f12726edccd
Cr-Commit-Position: refs/heads/master@{#294633}

[sky, 2014-09-12 15:52:48]

LGTM

[tfarina, 2014-09-12 17:18:44]

The CQ bit was checked by tfarina@chromium.org

[commit-bot: I haz the power, 2014-09-12 17:19:44]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patchset/565143002/1

[commit-bot: I haz the power, 2014-09-12 19:32:08]

Committed patchset #1 (id:1) as 0adcf6312f8901dbe0ea6a1da3ac74c58f48f96e

[commit-bot: I haz the power, 2014-09-12 19:35:48]

Patchset 1 (id:??) landed as
https://crrev.com/5631bd75102560b6ba31a809fe319f12726edccd
Cr-Commit-Position: refs/heads/master@{#294633}