Update from https://crrev.com/305340

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 8f5432f9e8a1fe4d99a87da15c2e462aa99c3f26..677cb63cd14e508c0135b36df62bd4242d4043a7 100755
--- a/tools/valgrind/chrome_tests.py
+++ b/tools/valgrind/chrome_tests.py
@@ -470,6 +470,9 @@ class ChromeTests:
   def TestUIBaseUnit(self):
     return self.SimpleTest("chrome", "ui_base_unittests")
 
+  def TestUIChromeOS(self):
+    return self.SimpleTest("chrome", "ui_chromeos_unittests")
+
   def TestURL(self):
     return self.SimpleTest("chrome", "url_unittests")
 
@@ -712,6 +715,7 @@ class ChromeTests:
     "sync_integration_tests": TestSyncIntegration,
     "sync_integration": TestSyncIntegration,
     "ui_base_unit": TestUIBaseUnit,       "ui_base_unittests": TestUIBaseUnit,
+    "ui_chromeos": TestUIChromeOS, "ui_chromeos_unittests": TestUIChromeOS,
     "unit": TestUnit,            "unit_tests": TestUnit,
     "url": TestURL,              "url_unittests": TestURL,
     "views": TestViews,          "views_unittests": TestViews,