Diable cloud import when Files.app launches as a dialog.

Diable cloud import when Files.app launches as a dialog.

- instantiate ImportController only when the Files.app type is PAGE_FULL.
- remove unused flag 'importEnabled_'.

BUG=454148
TEST=manual test

Committed: https://crrev.com/df0e26664beb1101a3325ead9174cffcd0d33f72
Cr-Commit-Position: refs/heads/master@{#327305}

[fukino, 2015-04-28 04:37:46]

fukino@chromium.org changed reviewers:
+ smckay@chromium.org

[fukino, 2015-04-28 04:37:46]

PTAL. Thanks!

[Steve McKay, 2015-04-28 16:31:48]

The CQ bit was checked by smckay@chromium.org

[Steve McKay, 2015-04-28 16:31:49]

lgtm

[commit-bot: I haz the power, 2015-04-28 16:32:21]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1109073002/1

[commit-bot: I haz the power, 2015-04-28 16:59:26]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-28 17:00:23]

Patchset 1 (id:??) landed as
https://crrev.com/df0e26664beb1101a3325ead9174cffcd0d33f72
Cr-Commit-Position: refs/heads/master@{#327305}