Revert of Pinch/Zoom Infrastructure & Plumbing CL (https://codereview.chromium.org/23983047/)

Reason for revert:
Broke Linux ASAN Tests (3) bot.

Original issue's description:
> Pinch/Zoom Infrastructure & Plumbing CL
> 
> This CL supplies the necessary changes to CC to support the
> inner/outer viewport model for pinch-zoom and fixed-position
> elements. The specification for these changes is contained in
> the document "Layer-based Solution for Pinch Zoom / Fixed
> Position".
> 
> It incorporates a change to how scrollbar parameters are
> computed (removes the notion of max_scroll_offset as a
> quantity set be the embedder, and instead inferred from the
> relative sizes of a clip layer w.r.t. the scroll layer).
> 
> Scrollbars are generalized so that a layer may have more than
> two scrollbars, and the parameters of the scrollbar are set
> w.r.t. the sizes and positions of a clip and a scroll layer.
> Further, changes to the scrip/scroll layer automatically
> notify any attached scrollbars.
> 
> The CL also removes existing references to root_scroll_layer
> from LTH, LTI and LTHI and replaces them with either
> Inner/OuterViewportScrollLayer (dual-layer operation only
> exists at present if the --enable-pinch-virtual-viewport flag
> is specified, otherwise behavior is unchanged).
> 
> Logic is added to (i) combine scroll offsets for the two
> viewports before passing it to the embedder, and (ii)
> splitting any offsets received from the embedder
> appropriately between the two viewports.
> 
> This CL relies on https://codereview.chromium.org/138453004/
> for changes in Blink to support it.
> 
> BUG=148816
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=246812
> 
> R=aelias@chromium.org, enne@chromium.org, joi@chromium.org, piman@chromium.org, sky@chromium.org
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=247684

TBR=enne@chromium.org,aelias@chromium.org,joi@chromium.org,sky@chromium.org,piman@chromium.org,tony@chromium.org,wjmaclean@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=148816

Review URL: https://codereview.chromium.org/135183016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247688 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247688