[tools][cts][roll] Include URL to build log

Change-Id: I6fcbd68bd92428bdf9b219505691c89cea2c4ca7
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/176461
Commit-Queue: Ben Clayton <bclayton@google.com>
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: dan sinclair <dsinclair@chromium.org>
diff --git a/tools/src/cmd/cts/common/build.go b/tools/src/cmd/cts/common/build.go
index 97ad277..967bb18 100644
--- a/tools/src/cmd/cts/common/build.go
+++ b/tools/src/cmd/cts/common/build.go
@@ -169,7 +169,7 @@
 			if err != nil {
 				return nil, err
 			}
-			log.Printf("started build: %+v", build)
+			log.Printf("started build: %+v\nLogs at: https://ci.chromium.org/ui/b/%v", build, build.ID)
 			builds[name] = build
 		}
 	}