DRM fixes

- Parse multiple kids from default_KID. It's specified as a whitespace
  separated list of UUIDs rather than a single UUID.
- Opportunistically proceed with playback in cases where the manifest
  only defines a single SchemeData with the common PSSH UUID. In such
  cases the manifest isn't saying anything about which specific DRM
  schemes it supports.

Issue: #3630

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=180675056

RELEASENOTES.md

@@ -26,6 +26,9 @@
   positions.
   * Note: `SeekParameters` are only currently effective when playing
     `ExtractorMediaSource`s (i.e. progressive streams).
+* DRM: Optimistically attempt playback of DRM protected content that does not
+  declare scheme specific init data
+  ([#3630](https://github.com/google/ExoPlayer/issues/3630)).
 * DASH: Support DASH manifest EventStream elements.
 * HLS: Add opt-in support for chunkless preparation in HLS. This allows an
   HLS source to finish preparation without downloading any chunks, which can

library/core/src/main/java/com/google/android/exoplayer2/drm/DefaultDrmSessionManager.java

@@ -23,6 +23,7 @@
 import android.support.annotation.IntDef;
 import android.support.annotation.NonNull;
 import android.text.TextUtils;
+import android.util.Log;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.Player;
 import com.google.android.exoplayer2.drm.DefaultDrmSession.ProvisioningManager;
@@ -87,7 +88,6 @@ public interface EventListener {
    * The key to use when passing CustomData to a PlayReady instance in an optional parameter map.
    */
   public static final String PLAYREADY_CUSTOM_DATA_KEY = "PRCustomData";
-  private static final String CENC_SCHEME_MIME_TYPE = "cenc";
 
   /** Determines the action to be done after a session acquired. */
   @Retention(RetentionPolicy.SOURCE)
@@ -109,6 +109,9 @@ public interface EventListener {
   /** Number of times to retry for initial provisioning and key request for reporting error. */
   public static final int INITIAL_DRM_REQUEST_RETRY_COUNT = 3;
 
+  private static final String TAG = "DrmSessionManager";
+  private static final String CENC_SCHEME_MIME_TYPE = "cenc";
+
   private final UUID uuid;
   private final ExoMediaDrm<T> mediaDrm;
   private final MediaDrmCallback callback;
@@ -350,8 +353,14 @@ public void setMode(@Mode int mode, byte[] offlineLicenseKeySetId) {
   public boolean canAcquireSession(@NonNull DrmInitData drmInitData) {
     SchemeData schemeData = getSchemeData(drmInitData, uuid, true);
     if (schemeData == null) {
-      // No data for this manager's scheme.
-      return false;
+      if (drmInitData.schemeDataCount == 1 && drmInitData.get(0).matches(C.COMMON_PSSH_UUID)) {
+        // Assume scheme specific data will be added before the session is opened.
+        Log.w(
+            TAG, "DrmInitData only contains common PSSH SchemeData. Assuming support for: " + uuid);
+      } else {
+        // No data for this manager's scheme.
+        return false;
+      }
     }
     String schemeType = drmInitData.schemeType;
     if (schemeType == null || C.CENC_TYPE_cenc.equals(schemeType)) {

library/dash/src/main/java/com/google/android/exoplayer2/source/dash/manifest/DashManifestParser.java

@@ -365,9 +365,14 @@ protected Pair<String, SchemeData> parseContentProtection(XmlPullParser xpp)
         case "urn:mpeg:dash:mp4protection:2011":
           schemeType = xpp.getAttributeValue(null, "value");
           String defaultKid = xpp.getAttributeValue(null, "cenc:default_KID");
-          if (defaultKid != null && !"00000000-0000-0000-0000-000000000000".equals(defaultKid)) {
-            UUID keyId = UUID.fromString(defaultKid);
-            data = PsshAtomUtil.buildPsshAtom(C.COMMON_PSSH_UUID, new UUID[] {keyId}, null);
+          if (!TextUtils.isEmpty(defaultKid)
+              && !"00000000-0000-0000-0000-000000000000".equals(defaultKid)) {
+            String[] defaultKidStrings = defaultKid.split("\\s+");
+            UUID[] defaultKids = new UUID[defaultKidStrings.length];
+            for (int i = 0; i < defaultKidStrings.length; i++) {
+              defaultKids[i] = UUID.fromString(defaultKidStrings[i]);
+            }
+            data = PsshAtomUtil.buildPsshAtom(C.COMMON_PSSH_UUID, defaultKids, null);
             uuid = C.COMMON_PSSH_UUID;
           }
           break;