Make VR latency results compatible with perf dashboard, refactor into classes

testing/buildbot/gn_isolate_map.pyl

 ## Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This is a .pyl, or "Python Literal", file. You can treat it just like a
 # .json file, with the following exceptions:
 # * all keys must be quoted (use single quotes, please);
 # * comments are allowed, using '#' syntax; and
 # * trailing commas are allowed.
 
@@ skipping 144 matching lines @@
   },
   "aura_builder": {
     "label": "//:aura_builder",
     "type": "additional_compile_target",
   },
   "aura_unittests": {
     "label": "//ui/aura:aura_unittests",
     "type": "windowed_test_launcher",
   },
   "motopho_latency_test": {
-    "label": "//chrome/test/vr/perf/latency/:motopho_latency_test",
+    "label": "//chrome/test/vr/perf:motopho_latency_test",
     "type": "script",
     "script": "//chrome/test/vr/perf/latency/run_latency_test.py",
     "args": [
       "--output-dir=${ISOLATED_OUTDIR}",
       "-v",
     ],
   },
   "base_junit_tests": {
     "label": "//base:base_junit_tests",
     "type": "junit_test",
@@ skipping 938 matching lines @@
   },
   "wm_unittests": {
     "label": "//ui/wm:wm_unittests",
     "type": "windowed_test_launcher",
   },
   "wtf_unittests": {
     "label": "//third_party/WebKit/Source/platform/wtf:wtf_unittests",
     "type": "console_test_launcher",
   },
 }