Add the ability to select a source image to use in the code.

A much farther ranging change than I suspected.

Basically add a 'source' integer to every Try, store that in the database with every Try, add the source to the computation of the hash, and load and use the 'source' value when navigating history.

BUG=skia:
R=mtklein@google.com

Author: jcgregorio@google.com

Review URL: https://codereview.chromium.org/294903017

git-svn-id: http://skia.googlecode.com/svn/trunk@14960 2bbb7eff-a529-9590-31e7-b0007b416f81
8 files changed