Revert of Unify desktop and Android tab helper instantiation. (https://codereview.chromium.org/144443003/)

Reason for revert:
This causes Clank to crash at startup, and makes tests fail http://build.chromium.org/p/chromium.linux/builders/Android%20Tests/builds/11575

Tried the revert locally, and Clank started normally.

Original issue's description:
> Unify desktop and Android tab helper instantiation.
> 
> BUG=337600
> TEST=zero visible change
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=247676

TBR=yfriedman@chromium.org,jam@chromium.org,avi@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=337600

Review URL: https://codereview.chromium.org/149393004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247682 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247682