Add robohornet as an animation test

tools/perf/page_sets/animations.json

 {
   "description": "A collection of animation performance tests",
   "pages": [
-    {"url": "file:///animations/keyframed_animations.html"},
-    {"url": "file:///animations/transform_transitions.html"}
+    {
+      "url": "file:///animations/keyframed_animations.html",
+      "why": "Tests various keyframed animations.",
+      "smoothness": {
+        "action": "wait_interaction",
+        "duration": 5
+      }
+    },
+    {
+      "url": "file:///animations/transform_transitions.html",
+      "why": "Tests various transitions.",
+      "smoothness": {
+        "action": "wait_interaction",
+        "duration": 5
+      }
+    },
+    {
+      "url": "http://ie.microsoft.com/testdrive/performance/robohornetpro/",
+      "why": "Login page is slow because of ineffecient transform operations",
+      "smoothness": {
+        "action": "wait_interaction",
+        "duration": 5
+      }
+    }
   ]
 }