API 27 is O mr1

Change-Id: I8de665e6fb22ed588b8b9ed81416fde5289658b1
diff --git a/src/main/java/com/android/tools/r8/utils/AndroidApiLevel.java b/src/main/java/com/android/tools/r8/utils/AndroidApiLevel.java
index 47bd02e..9f40791 100644
--- a/src/main/java/com/android/tools/r8/utils/AndroidApiLevel.java
+++ b/src/main/java/com/android/tools/r8/utils/AndroidApiLevel.java
@@ -10,7 +10,8 @@
  */
 public enum AndroidApiLevel {
   LATEST(-1),
-  P(27),
+  P(28),
+  O_MR1(27),
   O(26),
   N_MR1(25),
   N(24),
@@ -133,6 +134,8 @@
       case 26:
         return O;
       case 27:
+        return O_MR1;
+      case 28:
         return P;
       default:
         return LATEST;
diff --git a/src/main/java/com/android/tools/r8/utils/DexVersion.java b/src/main/java/com/android/tools/r8/utils/DexVersion.java
index c9fa818..7406227 100644
--- a/src/main/java/com/android/tools/r8/utils/DexVersion.java
+++ b/src/main/java/com/android/tools/r8/utils/DexVersion.java
@@ -51,6 +51,7 @@
       case P:
         return DexVersion.V39;
       case LATEST:
+      case O_MR1:
       case O:
         return DexVersion.V38;
       case N_MR1: