fix(drm): Fix support for multi-period encrypted live

To support encrypted, multi-period live streams, you must initialize
the CDM whenever there is a license server config, without regard for
whether or not there is encryption signalled in a manifest.

If you join the stream during a clear ad, and there isn't enough
rewind allowed to see any encrypted periods at the time you join, the
manifest may not indicate encryption.  If we start playback without
setting up decryption, we would fail later when an encrypted period
appeared.

This issue affected releases v3.0.0 - v3.0.5.

Fixes shaka-project#2979
Fixes shaka-project#2645

Change-Id: Ic7ddcf46843178e6a3ce0b1d663da40dc9f4be8f

lib/media/drm_engine.js

@@ -296,10 +296,10 @@ shaka.media.DrmEngine = class {
     const clearKeyDrmInfo = this.configureClearKey_();
     if (clearKeyDrmInfo) {
       for (const variant of variants) {
-        if (variant.video && variant.video.encrypted) {
+        if (variant.video) {
           variant.video.drmInfos = [clearKeyDrmInfo];
         }
-        if (variant.audio && variant.audio.encrypted) {
+        if (variant.audio) {
           variant.audio.drmInfos = [clearKeyDrmInfo];
         }
       }
@@ -1763,10 +1763,10 @@ shaka.media.DrmEngine = class {
     });
 
     for (const variant of variants) {
-      if (variant.video && variant.video.encrypted) {
+      if (variant.video) {
         variant.video.drmInfos = drmInfos;
       }
-      if (variant.audio && variant.audio.encrypted) {
+      if (variant.audio) {
         variant.audio.drmInfos = drmInfos;
       }
     }