Add new OOM adjustment for the "previous" process.

This is the process that you had previously been interacting with
in the UI before the current one.  Treating it specially should
allow us to improve the scenario of switching back and forth
between two apps.

Also add API constent for ICS MR1.

Change-Id: Ib3fe4df36b270be11dfd6b7e8d107c9994058a4d

core/java/android/os/Build.java

@@ -277,7 +277,7 @@ public class Build {
         public static final int HONEYCOMB_MR2 = 13;
 
         /**
-         * Android 4.0.
+         * October 2011: Android 4.0.
          *
          * <p>Applications targeting this or a later release will get these
          * new changes in behavior:</p>
@@ -309,6 +309,11 @@ public class Build {
          * </ul>
          */
         public static final int ICE_CREAM_SANDWICH = 14;
+
+        /**
+         * Android 4.1.
+         */
+        public static final int ICE_CREAM_SANDWICH_MR1 = 15;
     }
     
     /** The type of build, like "user" or "eng". */