Refactoring media notification

chrome/android/java/src/org/chromium/chrome/browser/media/ui/MediaButtonReceiver.java

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.media.ui;
 
 import android.content.BroadcastReceiver;
-import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
-import android.content.pm.PackageManager;
-import android.content.pm.ResolveInfo;
-
-import java.util.List;
 
 /**
  * MediaButtonReceiver is a basic BroadcastReceiver class that receives
  * ACTION_MEDIA_BUTTON from a MediaSessionCompat. It then forward these intents
  * to the service listening to them.
  * This is there for backward compatibility with JB_MR0 and JB_MR1.
  */
 public abstract class MediaButtonReceiver extends BroadcastReceiver {
-    private static final String LISTENER_SERVICE_CLASS_NAME =
-            "org.chromium.chrome.browser.media.ui"
-            + "MediaNotificationManager$ListenerService";
-    public static final String EXTRA_NOTIFICATION_ID =
-            "MediaNotificationManager.ListenerService.NOTIFICATION_ID";
-
-    public abstract int getNotificationId();
+    public abstract String getServiceClassName();
 
     @Override
     public void onReceive(Context context, Intent intent) {
-        Intent queryIntent = new Intent(Intent.ACTION_MEDIA_BUTTON);
-        queryIntent.setPackage(context.getPackageName());
-
-        PackageManager pm = context.getPackageManager();
-        List<ResolveInfo> infos = pm.queryIntentServices(queryIntent, 0);
-        assert infos.size() == 1;
-
-        ResolveInfo info = infos.get(0);
-        ComponentName component = new ComponentName(info.serviceInfo.packageName,
-                info.serviceInfo.name);
-        assert LISTENER_SERVICE_CLASS_NAME.equals(component.getClassName());
-
-        intent.setComponent(component);
-        intent.putExtra(EXTRA_NOTIFICATION_ID, getNotificationId());
+        intent.setClassName(context, getServiceClassName());
         context.startService(intent);

[whywhat, 2015/12/09 16:59:27]

Why is setClassName() equivalent to setComponent() then? Why do we get rid of
the checks above?

[Zhiqiang Zhang (Slow), 2015/12/09 18:02:55]

I checked the Android reference. setClassName() is a convenience way of calling
setComponent(). Because we know that PlaybackMediaButtonReceiver will only
forward to PlaybackListenerService (and the same with Presentation), directly
setting the service name should not be a problem.

The check above was incorrect (see LISTENER_SERVICE_CLASS_NAME). The assertions
don't fail on many devices. So I think we don't need that check. If the service
cannot be started, we can found it in adb logcat.

     }
 }