Set explicit export attributes in all demo apps

Starting with Android 12 all components of an app that have an intent filter need to have an explicit attribute android:export that is set to either true or false. If a component filters for the MAIN or a VIEW action it needs the attribute explicitly set to true. Prior to Android 12 these were exported implicitly.

See https://medium.com/androiddevelopers/lets-be-explicit-about-our-intent-filters-c5dbe2dbdce0

PiperOrigin-RevId: 358368785

demos/cast/src/main/AndroidManifest.xml

@@ -31,7 +31,8 @@
     <activity android:name="com.google.android.exoplayer2.castdemo.MainActivity"
     <activity android:name="com.google.android.exoplayer2.castdemo.MainActivity"
         android:configChanges="keyboard|keyboardHidden|orientation|screenSize|screenLayout|smallestScreenSize|uiMode"
         android:configChanges="keyboard|keyboardHidden|orientation|screenSize|screenLayout|smallestScreenSize|uiMode"
         android:launchMode="singleTop" android:label="@string/application_name"
         android:launchMode="singleTop" android:label="@string/application_name"
-        android:theme="@style/Theme.AppCompat">
+        android:theme="@style/Theme.AppCompat"
+        android:exported="true">
       <intent-filter>
       <intent-filter>
         <action android:name="android.intent.action.MAIN"/>
         <action android:name="android.intent.action.MAIN"/>
         <category android:name="android.intent.category.LAUNCHER"/>
         <category android:name="android.intent.category.LAUNCHER"/>

demos/main/src/main/AndroidManifest.xml

@@ -41,7 +41,8 @@
     <activity android:name="com.google.android.exoplayer2.demo.SampleChooserActivity"
     <activity android:name="com.google.android.exoplayer2.demo.SampleChooserActivity"
         android:configChanges="keyboardHidden"
         android:configChanges="keyboardHidden"
         android:label="@string/application_name"
         android:label="@string/application_name"
-        android:theme="@style/Theme.AppCompat">
+        android:theme="@style/Theme.AppCompat"
+        android:exported="true">
       <intent-filter>
       <intent-filter>
         <action android:name="android.intent.action.MAIN"/>
         <action android:name="android.intent.action.MAIN"/>
         <category android:name="android.intent.category.LAUNCHER"/>
         <category android:name="android.intent.category.LAUNCHER"/>
@@ -65,7 +66,8 @@
         android:configChanges="keyboard|keyboardHidden|orientation|screenSize|screenLayout|smallestScreenSize|uiMode"
         android:configChanges="keyboard|keyboardHidden|orientation|screenSize|screenLayout|smallestScreenSize|uiMode"
         android:launchMode="singleTop"
         android:launchMode="singleTop"
         android:label="@string/application_name"
         android:label="@string/application_name"
-        android:theme="@style/PlayerTheme">
+        android:theme="@style/PlayerTheme"
+        android:exported="true">
       <intent-filter>
       <intent-filter>
         <action android:name="com.google.android.exoplayer.demo.action.VIEW"/>
         <action android:name="com.google.android.exoplayer.demo.action.VIEW"/>
         <category android:name="android.intent.category.DEFAULT"/>
         <category android:name="android.intent.category.DEFAULT"/>

demos/surface/src/main/AndroidManifest.xml

@@ -21,7 +21,8 @@
   <application
   <application
     android:allowBackup="false"
     android:allowBackup="false"
     android:icon="@mipmap/ic_launcher"
     android:icon="@mipmap/ic_launcher"
-    android:label="@string/application_name">
+    android:label="@string/application_name"
+    android:exported="true">
     <activity android:name=".MainActivity">
     <activity android:name=".MainActivity">
       <intent-filter>
       <intent-filter>
         <action android:name="android.intent.action.MAIN"/>
         <action android:name="android.intent.action.MAIN"/>