Initial code for Gallery2.

fix: 5176434

Change-Id: I041e282b9c7b34ceb1db8b033be2b853bb3a992c

proguard.flags

+# Keep all classes extended from com.android.gallery3d.common.Entry
+# Since we annotate on the fields and use reflection to create SQL
+# according to those field.
+
+-keep class * extends com.android.gallery3d.common.Entry {
+    @com.android.gallery3d.common.Entry$Column <fields>;
+}