Add receiver flavor to CastDemo

PiperOrigin-RevId: 224310086

demos/cast/build.gradle

@@ -49,6 +49,16 @@ android {
         disable 'MissingTranslation'
     }
 
+    flavorDimensions "receiver"
+
+    productFlavors {
+        defaultCast {
+            dimension "receiver"
+            manifestPlaceholders =
+                    [castOptionsProvider: "com.google.android.exoplayer2.ext.cast.DefaultCastOptionsProvider"]
+        }
+    }
+
 }
 
 dependencies {

demos/cast/src/main/AndroidManifest.xml

@@ -23,7 +23,7 @@
       android:largeHeap="true" android:allowBackup="false">
 
     <meta-data android:name="com.google.android.gms.cast.framework.OPTIONS_PROVIDER_CLASS_NAME"
-        android:value="com.google.android.exoplayer2.ext.cast.DefaultCastOptionsProvider" />
+        android:value="${castOptionsProvider}" />
 
     <activity android:name="com.google.android.exoplayer2.castdemo.MainActivity"
         android:configChanges="keyboard|keyboardHidden|orientation|screenSize|screenLayout|smallestScreenSize|uiMode"