Add Gpu Tracing to Ganesh

BUG=skia:2316
R=bsalomon@google.com, tomhudson@google.com

Author: egdaniel@google.com

Review URL: https://codereview.chromium.org/184443003

git-svn-id: http://skia.googlecode.com/svn/trunk@13936 2bbb7eff-a529-9590-31e7-b0007b416f81
15 files changed