Add Chrome Cleaner commit info to FoilVersionSpec

This keeps a record of which commits each version of the Chrome Cleanup
Tool is built with. Currently this information is stored in tags on the
internal repo, but this approach won't work when the tool is built from
the public repo.

Goes with commit http://shortn/_zVs7MpRCuC in the internal repo that
stores the commit hashes in the protobuf.

R=drubery

Bug: 1004848
Change-Id: I6ae4073f10f571b6b70d35085291b68720898287
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2253130Reviewed-by: Daniel Rubery <drubery@chromium.org>
Commit-Queue: Joe Mason <joenotcharles@chromium.org>
Cr-Commit-Position: refs/heads/master@{#781171}

chrome/chrome_cleaner/proto/uws_spec_by_version.proto

@@ -79,14 +79,30 @@ message FoilUwSData {
   repeated StaticRegistryFootprint registry_footprints = 5;
 }
 
+// The git SHA's of each repo that is used to build this version of the
+// reporter and cleaner.
+//
+// Next tag: 4.
+message CommitInfo {
+  // The commit of the root chromium repository.
+  optional string chromium_commit = 1;
+
+  // The commit of the src-internal repository.
+  optional string src_internal_commit = 2;
+
+  // The commit of the chrome/chrome_cleaner/internal repository.
+  optional string chrome_cleaner_internal_commit = 3;
+}
+
 // Specifies all UwS recognized by a given version of the reporter or cleaner.
 //
 // FoilVersionSpec is a legacy name that must be kept because existing analysis
 // tools use it.
 //
-// Next tag: 3.
+// Next tag: 4.
 message FoilVersionSpec {
   optional string version = 1;
+  optional CommitInfo commit_info = 3;
   repeated FoilUwSData uws = 2;
 }