Create jsondiff tool to capture diffs between two JSON expectations files.
This will be used to view diffs before committing rebaselines, or to review
exactly what changed between two baseline revisions in the past.

Part of Step 3 in https://goto.google.com/ChecksumTransitionDetail

R=scroggo@google.com

Review URL: https://codereview.chromium.org/18103005

git-svn-id: http://skia.googlecode.com/svn/trunk@9878 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/gm_json.py b/gm/gm_json.py
index 6ba3a26..cd41984 100644
--- a/gm/gm_json.py
+++ b/gm/gm_json.py
@@ -23,6 +23,12 @@
 JSONKEY_ACTUALRESULTS_NOCOMPARISON = 'no-comparison'
 JSONKEY_ACTUALRESULTS_SUCCEEDED = 'succeeded'
 
+JSONKEY_EXPECTEDRESULTS = 'expected-results'
+JSONKEY_EXPECTEDRESULTS_ALLOWEDDIGESTS = 'allowed-digests'
+JSONKEY_EXPECTEDRESULTS_IGNOREFAILURE = 'ignore-failure'
+
+JSONKEY_HASHTYPE_BITMAP_64BITMD5 = 'bitmap-64bitMD5'
+
 def LoadFromString(file_contents):
   """Loads the JSON summary written out by the GM tool.
      Returns a dictionary keyed by the values listed as JSONKEY_ constants