Revert r217952 to make behavior of horizontal scroll bar in page chrome://extensions keep consisten…

Revert r217952 to make behavior of horizontal scroll bar in page chrome://extensions keep consistence with chrome://settings.

This patch also fix issue 269450 using a "no-scroll" css style to remove the
scroll bar when showing the overlay in page chrome://extensions.

BUG=277974, 269450
TEST=1.Launch chrome & navigate to chrome://extensions/;
2.Zoom the page to 300% or till horizontal scroll bar appears;
3.Try to move the horizontal scroll bar & observe

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=219671

[zhchbin, 2013-08-24 02:34:15]

@miket, Sorry for the trouble I have made. @xiyuan's workaround for fixing
http://crbug.com/269450 seems have side effect. 
In this patch I revert my previous commit and use my original patch to deal with
the crbug.com/269450. In order to take care of the relayout problem, I didn't
came out a more general solution.

Sorry again. Please review.

[zhchbin, 2013-08-24 02:34:15]

@miket, Sorry for the trouble I have made. @xiyuan's workaround for fixing
http://crbug.com/269450 seems have side effect. 
In this patch I revert my previous commit and use my original patch to deal with
the crbug.com/269450. In order to take care of the relayout problem, I didn't
came out a more general solution.

Sorry again. Please review.

[miket_OOO, 2013-08-26 16:50:02]

Revert LGTM

[commit-bot: I haz the power, 2013-08-26 22:57:03]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/zhchbin@gmail.com/22859067/1

[commit-bot: I haz the power, 2013-08-27 00:06:34]

Step "update" is always a major failure.
Look at the try server FAQ for more details.
http://build.chromium.org/p/tryserver.chromium/buildstatus?builder=linux_clan...

[commit-bot: I haz the power, 2013-08-27 00:52:51]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/zhchbin@gmail.com/22859067/1

[commit-bot: I haz the power, 2013-08-27 03:18:05]

Change committed as 219671