Update from https://crrev.com/328418

tools/valgrind/chrome_tests.py

Index: tools/valgrind/chrome_tests.py
diff --git a/tools/valgrind/chrome_tests.py b/tools/valgrind/chrome_tests.py
index e8074f37f9e1f62bbdbd4d21c332c0e3a1c50ed9..571beb189e0ded9b3375484da1d2324b16bb7bb6 100755
--- a/tools/valgrind/chrome_tests.py
+++ b/tools/valgrind/chrome_tests.py
@@ -401,6 +401,9 @@ class ChromeTests:
   def TestMessageCenter(self):
     return self.SimpleTest("message_center", "message_center_unittests")
 
+  def TestMidi(self):
+    return self.SimpleTest("chrome", "midi_unittests")
+
   def TestMojoCommon(self):
     return self.SimpleTest("mojo_common", "mojo_common_unittests")
 
@@ -696,6 +699,7 @@ class ChromeTests:
     "media": TestMedia,          "media_unittests": TestMedia,
     "message_center": TestMessageCenter,
     "message_center_unittests" : TestMessageCenter,
+    "midi": TestMidi,             "midi_unittests": TestMidi,
     "mojo_common": TestMojoCommon,
     "mojo_system": TestMojoSystem,
     "mojo_public_system": TestMojoPublicSystem,