Add unit_tests bundle as a default compile target for Android.

PRESUBMIT.py

Index: PRESUBMIT.py
diff --git a/PRESUBMIT.py b/PRESUBMIT.py
index 009df4ce5a5cd0d55f1307976cb6f8d87d3c6bf5..ba38fedca0196e563c275661bb01302b3ff8329a 100644
--- a/PRESUBMIT.py
+++ b/PRESUBMIT.py
@@ -510,12 +510,10 @@ def GetPreferredTrySlaves(project, change):
   if all(re.search('[/_]android[/_.]', f) for f in files):
     return ['android']
 
-  trybots = ['win_rel', 'linux_rel', 'mac_rel', 'linux_clang:compile']
+  trybots = ['win_rel', 'linux_rel', 'mac_rel', 'linux_clang:compile',
+             'android']
   # match things like aurax11.cc or aura_oak.cc
   if any(re.search('[/_]aura', f) for f in files):
     trybots.append('linux_chromeos')
 
-  if not all(f.startswith('chrome/') for f in files):
-    trybots.append('android')
-
   return trybots