Revert of Widen GPU trigger condition (patchset #3 id:40001 of https://codereview.chromium.org/660133005/)

Reason for revert:
There's content that depends on the existing trigger in order to
opt-out of GPU rasterization. Since we're close to the branch point,
let's revert this and then try to expand again in M41.

Original issue's description:
> Widen GPU trigger condition
> 
> GPU rasterization will be triggered when viewports meet either of the 
> following conditions:
> 1) width=device-width, minimum-scale=X, where X >= 1.0
> 2) width=device-width, user-scalable=no
> 
> BUG=424469
> 
> Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=184566

BUG=424469

Review URL: https://codereview.chromium.org/685003008

git-svn-id: svn://svn.chromium.org/blink/trunk@184848 bbb929c8-8fbe-4397-9dbb-9b2b20218538