Merge "Give IAE for invalid sdk a message" am: dc3e45c584 am: d4707ec21e

Change-Id: If9afeb4f6532ab252ea1317c1a12f05de90a7362
diff --git a/apex/sdkext/framework/java/android/os/ext/SdkExtensions.java b/apex/sdkext/framework/java/android/os/ext/SdkExtensions.java
index d3b9397..a8a7eff 100644
--- a/apex/sdkext/framework/java/android/os/ext/SdkExtensions.java
+++ b/apex/sdkext/framework/java/android/os/ext/SdkExtensions.java
@@ -60,7 +60,7 @@
      */
     public static int getExtensionVersion(@SdkVersion int sdk) {
         if (sdk < VERSION_CODES.R) {
-            throw new IllegalArgumentException();
+            throw new IllegalArgumentException(String.valueOf(sdk) + " does not have extensions");
         }
         return R_EXTENSION_INT;
     }