Use the new PopupWindow overlap anchor methods

Allows developers to set one style attribute and AppCompat
will then forward it on to the framework impl.

BUG: 18245054
Change-Id: I3cf2e2224d0420e80342e162ad01be1fb4f3cc18
diff --git a/v4/build.gradle b/v4/build.gradle
index 1cf63e8..7ef9ba5 100644
--- a/v4/build.gradle
+++ b/v4/build.gradle
@@ -30,6 +30,7 @@
 def api20SS        = createApiSourceset('api20',        'api20',         '20', kitkatSS)
 def api21SS        = createApiSourceset('api21',        'api21',         '21', api20SS)
 def api22SS        = createApiSourceset('api22',        'api22',         'current', api21SS)
+def api23SS        = createApiSourceset('api23',        'api23',         'current', api22SS)
 
 
 def createApiSourceset(String name, String folder, String apiLevel, SourceSet previousSource) {