analysis/appengine/template: truncate long label values

Change-Id: Ica888f19254759a060015e9635cffd0231721dd4
Reviewed-on: https://go-review.googlesource.com/35946
Reviewed-by: Russ Cox <rsc@golang.org>
diff --git a/analysis/appengine/template/compare.html b/analysis/appengine/template/compare.html
index 3f985f2..d0f5577 100644
--- a/analysis/appengine/template/compare.html
+++ b/analysis/appengine/template/compare.html
@@ -60,6 +60,12 @@
 #labels .diff {
   padding-bottom: 1em;
 }
+#labels .diff table td {
+  max-width: 20em;
+  white-space: nowrap;
+  overflow: hidden;
+  text-overflow: ellipsis;
+}
     </style>
   </head>
   <body>