Revert of Revert of Remove smiluate-touch-screen-with-mouse content flag.

Revert of Revert of Remove smiluate-touch-screen-with-mouse content flag. (https://codereview.chromium.org/260123003/)

Reason for revert:
I meant to revert https://codereview.chromium.org/250923005/ , not this one.

Original issue's description:
> Revert of Remove smiluate-touch-screen-with-mouse content flag. (https://codereview.chromium.org/258503003/)
> 
> Reason for revert:
> Somewhat speculative; looks like this caused TouchEmulatorTest failures on valgrind:
> 
> http://build.chromium.org/p/chromium.memory.fyi/builders/Linux%20Tests%20%28tsan%29%283%29/builds/11052
> 
> TouchEmulatorTest.Pinch:
> ../../content/browser/renderer_host/input/touch_emulator_unittest.cc:254: Failure
> Value of: ExpectedEvents()
> Actual: "TouchEnd GestureFlingStart"
> Expected: "TouchEnd GestureScrollEnd"
> 
> etc
> 
> Original issue's description:
> > Remove smiluate-touch-screen-with-mouse content flag.
> > 
> > This is duplicated functionality now, as one can use DevTools touch emulation instead.
> > 
> > BUG=337142
> > 
> > Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=266549
> 
> TBR=aelias@chromium.org,jochen@chromium.org,dgozman@chromium.org
> NOTREECHECKS=true
> NOTRY=true
> BUG=337142
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=266608

TBR=aelias@chromium.org,jochen@chromium.org,dgozman@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=337142
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=266609

[Nico, 2014-04-28 18:27:05]

Created Revert of Revert of Remove smiluate-touch-screen-with-mouse content
flag.

[commit-bot: I haz the power, 2014-04-28 18:28:31]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/thakis@chromium.org/256203003/1

[commit-bot: I haz the power, 2014-04-28 18:29:25]

Change committed as 266609