Upgrade Integration Test to Use Latest EME Spec

(This is a merge of
https://widevine-internal-review.googlesource.com/#/c/10140/
from the Widevine CDM repo.)

Updates the integration test from using "video/avc" to "cenc".

Bug: 13731637
Change-Id: Idfa0eabb6eb359a3d08008952bff495bea164cc7

libwvdrmengine/test/java/src/com/widevine/test/KeyRequester.java

@@ -42,7 +42,7 @@ public class KeyRequester {
                 retryRequest = false;
 
                 try {
-                    drmRequest = drm.getKeyRequest(sessionId, mPssh, "video/avc",
+                    drmRequest = drm.getKeyRequest(sessionId, mPssh, "cenc",
                                                    MediaDrm.KEY_TYPE_STREAMING, null);
                 } catch (NotProvisionedException e) {
                     Log.i(TAG, "Invalid certificate, reprovisioning");