Fast implementation of QuadTree

Rewritten to avoid memory allocations.

BUG=skia:2242
R=tomhudson@google.com, mtklein@google.com, reed@google.com, robertphillips@google.com

Author: iancottrell@google.com

Review URL: https://codereview.chromium.org/187233002

git-svn-id: http://skia.googlecode.com/svn/trunk@13826 2bbb7eff-a529-9590-31e7-b0007b416f81
10 files changed