Revert "Support viewport in content_shell."

This patch changes layout tests on Android to be ran using a 980x735
canvas instead of an 800x600 one, basically breaking everything. The
"WebKit Android (Nexus4)" tester is currently red because of this.

> Support viewport in content_shell.
>
> Viewport preferences are overridden even with the --enable-viewport
> flag passed in.
>
> BUG=343993
>

BUG=343993, 345221
NOTRY=true
TBR=zeeshankq@chromium.org, aelias, jochen

Review URL: https://codereview.chromium.org/171603015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@252234 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 252234