Omaha: Send a channel identifier and updater version in the UC.

This data is already sent in the <app> element, but sending it in
<request> ties it to the updater and enables Omaha's cross-product
monitoring and logging to be more aware of this updater.

Bug: 1110339
Change-Id: Ib4ec718a281664e3732f6ca060be7300902fa1a9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2418474
Auto-Submit: Joshua Pawlicki <waffles@chromium.org>
Reviewed-by: Tommy Nyquist <nyquist@chromium.org>
Commit-Queue: Joshua Pawlicki <waffles@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809316}

chrome/android/java/src/org/chromium/chrome/browser/omaha/RequestGenerator.java

@@ -72,7 +72,10 @@ public abstract class RequestGenerator {
             // Set up <request protocol=3.0 ...>
             serializer.startTag(null, "request");
             serializer.attribute(null, "protocol", "3.0");
-            serializer.attribute(null, "version", "Android-1.0.0.0");
+            serializer.attribute(null, "updater", "Android");
+            serializer.attribute(null, "updaterversion", versionName);
+            serializer.attribute(null, "updaterchannel",
+                    StringSanitizer.sanitize(BuildInfo.getInstance().hostPackageLabel));
             serializer.attribute(null, "ismachine", "1");
             serializer.attribute(null, "requestid", "{" + data.getRequestID() + "}");
             serializer.attribute(null, "sessionid", "{" + sessionID + "}");