Make coverage work without test defs.

Change-Id: I946df038e97dc5c2f40a4610d4076e13ab6bde37

testrunner/android_mk.py

@@ -115,6 +115,10 @@ class AndroidMK(object):
     """
     return identifier in self._includes
 
+  def IncludesMakefilesUnder(self):
+    """Check if makefile has a 'include makefiles under here' rule"""
+    return self.HasInclude('call all-makefiles-under,$(LOCAL_PATH)')
+
   def HasJavaLibrary(self, library_name):
     """Check if library is specified as a local java library in makefile.
 
@@ -168,4 +172,4 @@ def CreateAndroidMK(path, filename=AndroidMK.FILENAME):
     mk._ParseMK(mk_path)
     return mk
   else:
-    return None
+    return None