Revert of Gallery: capture escape key in full screen by adding a permission.

Revert of Gallery: capture escape key in full screen by adding a permission. (patchset #2 id:20001 of https://codereview.chromium.org/1149323006/)

Reason for revert:
All of Gallery Material Redesign will happen in M46.

Original issue's description:
> Gallery: capture escape key in full screen by adding a permission.
>
> BUG=497011
> TEST=manually tested; Maximize Gallery and press slideshow button. Confirm that it goes to slideshow mode. After it, press escape key and confirm that it goes back to the original mode.
>
> Committed: https://crrev.com/7d1560ccb3dfee3c9f1510b035f67261b0b88d8f
> Cr-Commit-Position: refs/heads/master@{#333246}

TBR=fukino@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=497011
Committed: https://crrev.com/77a209184fadf86ea0386608f0c72de4a35b4706
Cr-Commit-Position: refs/heads/master@{#333673}

[yawano, 2015-06-10 03:17:45]

Created Revert of Gallery: capture escape key in full screen by adding a
permission.

[commit-bot: I haz the power, 2015-06-10 03:18:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1174733005/1

[commit-bot: I haz the power, 2015-06-10 03:18:45]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-10 03:20:24]

Patchset 1 (id:??) landed as
https://crrev.com/77a209184fadf86ea0386608f0c72de4a35b4706
Cr-Commit-Position: refs/heads/master@{#333673}