[Android] Switch to DeviceUtils versions of Ls, SetJavaAsserts, GetProp, and SetProp.

build/android/enable_asserts.py

Index: build/android/enable_asserts.py
diff --git a/build/android/enable_asserts.py b/build/android/enable_asserts.py
index 8dd44f1901b32746a26931eb491e781fcd0cefef..0e30bc2a1736d529511b038007f6e9bc707c2b7e 100755
--- a/build/android/enable_asserts.py
+++ b/build/android/enable_asserts.py
@@ -27,7 +27,7 @@ def main(argv):
   devices = android_commands.GetAttachedDevices()
   for device in [device_utils.DeviceUtils(serial) for serial in devices]:
     if options.set_asserts != None:
-      if device.old_interface.SetJavaAssertsEnabled(options.set_asserts):
+      if device.SetJavaAsserts(options.set_asserts):
         # TODO(jbudorick) How to best do shell restarts after the
         #                 android_commands refactor?
         device.RunShellCommand('stop')