[Chromecast] Add getDevices to CastAudioManager.

Bug: Internal b/147703983

Test: test with eureka-internal/355651.
Change-Id: I86a86df4844f3d6e6103f896061ba6d9c2b7599c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2055425Reviewed-by: Yuchen Liu <yucliu@chromium.org>
Reviewed-by: Simeon Anfinrud <sanfin@chromium.org>
Commit-Queue: Ziyang Cheng <ziyangch@chromium.org>
Cr-Commit-Position: refs/heads/master@{#741745}

chromecast/browser/android/apk/src/org/chromium/chromecast/shell/CastAudioManager.java

@@ -4,10 +4,13 @@
 
 package org.chromium.chromecast.shell;
 
+import android.annotation.TargetApi;
 import android.content.Context;
+import android.media.AudioDeviceInfo;
 import android.media.AudioManager;
 import android.media.audiopolicy.AudioPolicy;
 import android.os.Build;
+import android.os.Build.VERSION_CODES;
 import android.support.annotation.Nullable;
 
 import androidx.annotation.VisibleForTesting;
@@ -126,6 +129,11 @@ public class CastAudioManager {
         mInternal.unregisterAudioPolicyAsync(audioPolicy);
     }
 
+    @TargetApi(VERSION_CODES.M)
+    public AudioDeviceInfo[] getDevices(int flags) {
+        return mInternal.getDevices(flags);
+    }
+
     // TODO(sanfin): Do not expose this. All needed AudioManager methods can be adapted with
     // CastAudioManager.
     public AudioManager getInternal() {