Implement multi session to support DRM key rotation.

Spec: https://storage.googleapis.com/wvdocs/Widevine_DRM_Android_Using_Key_Rotation.pdf

1. Implement multisession to support drm key rotation
2. Put MediaDrmEventListener back to manager since this is a per mediaDrm thing.
3. It seems diffrenciate between single/multi session is unnecessary.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=167602965

demos/main/src/main/java/com/google/android/exoplayer2/demo/PlayerActivity.java

@@ -89,6 +89,7 @@ public class PlayerActivity extends Activity implements OnClickListener, EventLi
   public static final String DRM_SCHEME_UUID_EXTRA = "drm_scheme_uuid";
   public static final String DRM_LICENSE_URL = "drm_license_url";
   public static final String DRM_KEY_REQUEST_PROPERTIES = "drm_key_request_properties";
+  public static final String DRM_MULTI_SESSION = "drm_multi_session";
   public static final String PREFER_EXTENSION_DECODERS = "prefer_extension_decoders";
 
   public static final String ACTION_VIEW = "com.google.android.exoplayer.demo.action.VIEW";
@@ -264,13 +265,14 @@ public class PlayerActivity extends Activity implements OnClickListener, EventLi
       if (drmSchemeUuid != null) {
         String drmLicenseUrl = intent.getStringExtra(DRM_LICENSE_URL);
         String[] keyRequestPropertiesArray = intent.getStringArrayExtra(DRM_KEY_REQUEST_PROPERTIES);
+        boolean multiSession = intent.getBooleanExtra(DRM_MULTI_SESSION, false);
         int errorStringId = R.string.error_drm_unknown;
         if (Util.SDK_INT < 18) {
           errorStringId = R.string.error_drm_not_supported;
         } else {
           try {
             drmSessionManager = buildDrmSessionManagerV18(drmSchemeUuid, drmLicenseUrl,
-                keyRequestPropertiesArray);
+                keyRequestPropertiesArray, multiSession);
           } catch (UnsupportedDrmException e) {
             errorStringId = e.reason == UnsupportedDrmException.REASON_UNSUPPORTED_SCHEME
                 ? R.string.error_drm_unsupported_scheme : R.string.error_drm_unknown;
@@ -379,7 +381,8 @@ public class PlayerActivity extends Activity implements OnClickListener, EventLi
   }
 
   private DrmSessionManager<FrameworkMediaCrypto> buildDrmSessionManagerV18(UUID uuid,
-      String licenseUrl, String[] keyRequestPropertiesArray) throws UnsupportedDrmException {
+      String licenseUrl, String[] keyRequestPropertiesArray, boolean multiSession)
+      throws UnsupportedDrmException {
     HttpMediaDrmCallback drmCallback = new HttpMediaDrmCallback(licenseUrl,
         buildHttpDataSourceFactory(false));
     if (keyRequestPropertiesArray != null) {
@@ -389,7 +392,7 @@ public class PlayerActivity extends Activity implements OnClickListener, EventLi
       }
     }
     return new DefaultDrmSessionManager<>(uuid, FrameworkMediaDrm.newInstance(uuid), drmCallback,
-        null, mainHandler, eventLogger);
+        null, mainHandler, eventLogger, multiSession);
   }
 
   private void releasePlayer() {

demos/main/src/main/java/com/google/android/exoplayer2/demo/SampleChooserActivity.java

@@ -182,6 +182,7 @@ public class SampleChooserActivity extends Activity {
       UUID drmUuid = null;
       String drmLicenseUrl = null;
       String[] drmKeyRequestProperties = null;
+      boolean drmMultiSession = false;
       boolean preferExtensionDecoders = false;
       ArrayList<UriSample> playlistSamples = null;
       String adTagUri = null;
@@ -220,6 +221,9 @@ public class SampleChooserActivity extends Activity {
             reader.endObject();
             drmKeyRequestProperties = drmKeyRequestPropertiesList.toArray(new String[0]);
             break;
+          case "drm_multi_session":
+            drmMultiSession = reader.nextBoolean();
+            break;
           case "prefer_extension_decoders":
             Assertions.checkState(!insidePlaylist,
                 "Invalid attribute on nested item: prefer_extension_decoders");
@@ -242,15 +246,16 @@ public class SampleChooserActivity extends Activity {
         }
       }
       reader.endObject();
-
+      DrmInfo drmInfo = drmUuid == null ? null : new DrmInfo(drmUuid, drmLicenseUrl,
+          drmKeyRequestProperties, drmMultiSession);
       if (playlistSamples != null) {
         UriSample[] playlistSamplesArray = playlistSamples.toArray(
             new UriSample[playlistSamples.size()]);
-        return new PlaylistSample(sampleName, drmUuid, drmLicenseUrl, drmKeyRequestProperties,
-            preferExtensionDecoders, playlistSamplesArray);
+        return new PlaylistSample(sampleName, preferExtensionDecoders, drmInfo,
+            playlistSamplesArray);
       } else {
-        return new UriSample(sampleName, drmUuid, drmLicenseUrl, drmKeyRequestProperties,
-            preferExtensionDecoders, uri, extension, adTagUri);
+        return new UriSample(sampleName, preferExtensionDecoders, drmInfo, uri, extension,
+            adTagUri);
       }
     }
 
@@ -372,31 +377,47 @@ public class SampleChooserActivity extends Activity {
 
   }
 
-  private abstract static class Sample {
-
-    public final String name;
-    public final boolean preferExtensionDecoders;
+  private static final class DrmInfo {
     public final UUID drmSchemeUuid;
     public final String drmLicenseUrl;
     public final String[] drmKeyRequestProperties;
+    public final boolean drmMultiSession;
 
-    public Sample(String name, UUID drmSchemeUuid, String drmLicenseUrl,
-        String[] drmKeyRequestProperties, boolean preferExtensionDecoders) {
-      this.name = name;
+    public DrmInfo(UUID drmSchemeUuid, String drmLicenseUrl,
+        String[] drmKeyRequestProperties, boolean drmMultiSession) {
       this.drmSchemeUuid = drmSchemeUuid;
       this.drmLicenseUrl = drmLicenseUrl;
       this.drmKeyRequestProperties = drmKeyRequestProperties;
+      this.drmMultiSession = drmMultiSession;
+    }
+
+    public void updateIntent(Intent intent) {
+      Assertions.checkNotNull(intent);
+      intent.putExtra(PlayerActivity.DRM_SCHEME_UUID_EXTRA, drmSchemeUuid.toString());
+      intent.putExtra(PlayerActivity.DRM_LICENSE_URL, drmLicenseUrl);
+      intent.putExtra(PlayerActivity.DRM_KEY_REQUEST_PROPERTIES, drmKeyRequestProperties);
+      intent.putExtra(PlayerActivity.DRM_MULTI_SESSION, drmMultiSession);
+    }
+  }
+
+  private abstract static class Sample {
+    public final String name;
+    public final boolean preferExtensionDecoders;
+    public final DrmInfo drmInfo;
+
+    public Sample(String name, boolean preferExtensionDecoders, DrmInfo drmInfo) {
+      this.name = name;
       this.preferExtensionDecoders = preferExtensionDecoders;
+      this.drmInfo = drmInfo;
     }
 
     public Intent buildIntent(Context context) {
       Intent intent = new Intent(context, PlayerActivity.class);
       intent.putExtra(PlayerActivity.PREFER_EXTENSION_DECODERS, preferExtensionDecoders);
-      if (drmSchemeUuid != null) {
-        intent.putExtra(PlayerActivity.DRM_SCHEME_UUID_EXTRA, drmSchemeUuid.toString());
-        intent.putExtra(PlayerActivity.DRM_LICENSE_URL, drmLicenseUrl);
-        intent.putExtra(PlayerActivity.DRM_KEY_REQUEST_PROPERTIES, drmKeyRequestProperties);
+      if (drmInfo != null) {
+        drmInfo.updateIntent(intent);
       }
+
       return intent;
     }
 
@@ -408,10 +429,9 @@ public class SampleChooserActivity extends Activity {
     public final String extension;
     public final String adTagUri;
 
-    public UriSample(String name, UUID drmSchemeUuid, String drmLicenseUrl,
-        String[] drmKeyRequestProperties, boolean preferExtensionDecoders, String uri,
+    public UriSample(String name, boolean preferExtensionDecoders, DrmInfo drmInfo, String uri,
         String extension, String adTagUri) {
-      super(name, drmSchemeUuid, drmLicenseUrl, drmKeyRequestProperties, preferExtensionDecoders);
+      super(name, preferExtensionDecoders, drmInfo);
       this.uri = uri;
       this.extension = extension;
       this.adTagUri = adTagUri;
@@ -432,10 +452,9 @@ public class SampleChooserActivity extends Activity {
 
     public final UriSample[] children;
 
-    public PlaylistSample(String name, UUID drmSchemeUuid, String drmLicenseUrl,
-        String[] drmKeyRequestProperties, boolean preferExtensionDecoders,
+    public PlaylistSample(String name, boolean preferExtensionDecoders, DrmInfo drmInfo,
         UriSample... children) {
-      super(name, drmSchemeUuid, drmLicenseUrl, drmKeyRequestProperties, preferExtensionDecoders);
+      super(name, preferExtensionDecoders, drmInfo);
       this.children = children;
     }