Add win_drmemory_light trybot to default trybot list.

BUG=chromium:360054
TEST=None
R=henrika@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/11879004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5894 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index 5f913a9..d17c796 100644
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -219,6 +219,7 @@
       'win',
       'win_asan',
       'win_baremetal',
+      'win_drmemory_light',
       'win_rel',
       'win_x64_rel',
   ]