Implements a ContentProvider that can be used to provide binary attachments (e.g., images) to calls made via FacebookDialog. The NativeAppCallAttachmentStore class provides methods to attach and clean up the attachments.

Note that this ContentProvider is only necessary if an application wishes to attach images, etc., that are stored in memory and do not have another way to be referenced by a content URI. For images obtained from, e.g., the Camera or Gallery, that already have a content URI associated with them, use of this class is not necessary.

If an application wishes to attach images that are stored in-memory within the application, this content provider must be listed in the application's AndroidManifest.xml, and it should be named according to the pattern "com.facebook.app.NativeAppCallContentProvider{FACEBOOK_APP_ID}". See the getContentProviderName.getAttachmentUrl method.