Using Proguard to shrink apk size.

Contacts proguard.flags change, add keep class for tests.

BUG 27314641

Change-Id: I4a169e50602ebdcea197baa54f4f887a76acdeb5
(cherry picked from commit 6035674bd506f3c9bdb49c9ce271747d7eff229e)
diff --git a/src/com/android/contacts/ContactsApplication.java b/src/com/android/contacts/ContactsApplication.java
index f0dc91b..0ba1f02 100644
--- a/src/com/android/contacts/ContactsApplication.java
+++ b/src/com/android/contacts/ContactsApplication.java
@@ -33,8 +33,10 @@
 import com.android.contacts.common.util.Constants;
 import com.android.contacts.commonbind.analytics.AnalyticsUtil;
 
+import com.android.contacts.common.testing.NeededForTesting;
 import com.google.common.annotations.VisibleForTesting;
 
+@NeededForTesting
 public class ContactsApplication extends Application {
     private static final boolean ENABLE_LOADER_LOG = false; // Don't submit with true
     private static final boolean ENABLE_FRAGMENT_LOG = false; // Don't submit with true