Revert of Revision Info into GenericSet

docs/histogram-set-json-format.md

Index: docs/histogram-set-json-format.md
diff --git a/docs/histogram-set-json-format.md b/docs/histogram-set-json-format.md
index be9bc5b6330f7b7b4fb8727d9698eb36e0da1994..3366f7d1548c3f14172e23a6553d53bf2b992e6a 100644
--- a/docs/histogram-set-json-format.md
+++ b/docs/histogram-set-json-format.md
@@ -133,6 +133,7 @@
  * `RelatedHistogramMap`
  * `RelatedHistogramBreakdown`
  * `TelemetryInfo`
+ * `RevisionInfo`
  * `BuildbotInfo`
  * `Scalar`
 
@@ -158,6 +159,20 @@
  * `storyGroupingKeys`: dictionary mapping from strings to strings
  * `storysetRepeatCounter`: number
 
+### RevisionInfo
+
+This tracks revisions of the software under test to allow users to compare or
+merge results across revisions.
+
+ * `chromiumCommitPosition`: optional integer
+ * `v8CommitPosition`: optional integer
+ * `chromium`: array of 1 or 2 strings
+ * `v8`: array of 1 or 2 strings
+ * `catapult`: array of 1 or 2 strings
+ * `angle`: array of 1 or 2 strings
+ * `skia`: array of 1 or 2 strings
+ * `webrtc`: array of 1 or 2 strings
+
 ### BuildbotInfo
 
 This tracks buildbot parameters when the Histogram was produced to allow users