Add media perf benchamrk under network simulations.

tools/perf/benchmarks/media.py

Index: tools/perf/benchmarks/media.py
diff --git a/tools/perf/benchmarks/media.py b/tools/perf/benchmarks/media.py
index 7fcf6100853b1831989eb953a618a351988108e8..8ef0619ffea49fb716ecdffd93c4ea2f76b668f2 100644
--- a/tools/perf/benchmarks/media.py
+++ b/tools/perf/benchmarks/media.py
@@ -9,6 +9,11 @@ class Media(test.Test):
   test = media.Media
   page_set = 'page_sets/tough_video_cases.json'
 
+class MediaNetworkSimulation(test.Test):
+  """Obtains media metrics under different network simulations."""
+  test = media.Media
+  page_set = 'page_sets/media_cns_cases.json'
+
 class MediaAndroid(test.Test):
   """Obtains media metrics for key user scenarios on Android."""
   test = media.Media