Add the ability to select bbh type, and include quadtree support.

Add the ability to select bbh type, and include quadtree support.
This is a breaking change to tileGridSize flag added in 184543003, as it now defaults to a sensible value but does not implicitly turn on the tile grid bbh.

BUG=skia:2242
R=tomhudson@google.com, mtklein@google.com, skyostil@chromium.org, skyostil@google.com

Author: iancottrell@google.com

Review URL: https://codereview.chromium.org/183763022

git-svn-id: http://skia.googlecode.com/svn/trunk@13641 2bbb7eff-a529-9590-31e7-b0007b416f81