[devil] If possible, allow to enable root on user builds.

devil/devil/android/device_utils_test.py

Index: devil/devil/android/device_utils_test.py
diff --git a/devil/devil/android/device_utils_test.py b/devil/devil/android/device_utils_test.py
index 2490209631075502df03c9f81c035b8da05ef2b6..f5f2cb53228001b7a206e5aebdc4d61a248a1041 100755
--- a/devil/devil/android/device_utils_test.py
+++ b/devil/devil/android/device_utils_test.py
@@ -315,22 +315,22 @@ class DeviceUtilsEnableRootTest(DeviceUtilsTest):
 
   def testEnableRoot_succeeds(self):
     with self.assertCalls(
-        (self.call.device.IsUserBuild(), False),
-         self.call.adb.Root(),
-         self.call.device.WaitUntilFullyBooted()):
+        self.call.adb.Root(),
+        self.call.device.WaitUntilFullyBooted()):
       self.device.EnableRoot()
 
   def testEnableRoot_userBuild(self):
     with self.assertCalls(
+        (self.call.adb.Root(), self.AdbCommandError()),
         (self.call.device.IsUserBuild(), True)):
       with self.assertRaises(device_errors.CommandFailedError):
         self.device.EnableRoot()
 
   def testEnableRoot_rootFails(self):
     with self.assertCalls(
-        (self.call.device.IsUserBuild(), False),
-        (self.call.adb.Root(), self.CommandError())):
-      with self.assertRaises(device_errors.CommandFailedError):
+        (self.call.adb.Root(), self.AdbCommandError()),
+        (self.call.device.IsUserBuild(), False)):
+      with self.assertRaises(device_errors.AdbCommandFailedError):
         self.device.EnableRoot()