DeviceUtils: Fix SU command for pre-M devices

build/android/devil/android/device_utils_test.py

Index: build/android/devil/android/device_utils_test.py
diff --git a/build/android/devil/android/device_utils_test.py b/build/android/devil/android/device_utils_test.py
index 6276ff2b138613a55a9f15e34615d90d393bebff..883815e9ce9ed1436e36e561830766bea83f0f98 100755
--- a/build/android/devil/android/device_utils_test.py
+++ b/build/android/devil/android/device_utils_test.py
@@ -697,13 +697,13 @@ class DeviceUtilsSuTest(DeviceUtilsTest):
     with self.patch_call(
         self.call.device.build_version_sdk,
         return_value=version_codes.LOLLIPOP_MR1):
-      self.assertEquals('su -c foo', self.device._Su('foo'))
+      self.assertEquals("su -c 'foo bar'", self.device._Su('foo bar'))
 
   def testSu_mAndAbove(self):
     with self.patch_call(
         self.call.device.build_version_sdk,
         return_value=version_codes.MARSHMALLOW):
-      self.assertEquals('su 0 foo', self.device._Su('foo'))
+      self.assertEquals('su 0 foo bar', self.device._Su('foo bar'))
 
 
 class DeviceUtilsRunShellCommandTest(DeviceUtilsTest):