Wire thumbnails in archives in ExternalStorageProvider.

Bug: 20176812
Change-Id: Ibf421df1c26583b4b7c3a8516eac79ea0ef31ec3
diff --git a/packages/ExternalStorageProvider/src/com/android/externalstorage/ExternalStorageProvider.java b/packages/ExternalStorageProvider/src/com/android/externalstorage/ExternalStorageProvider.java
index bc09f3a..c6e5531 100644
--- a/packages/ExternalStorageProvider/src/com/android/externalstorage/ExternalStorageProvider.java
+++ b/packages/ExternalStorageProvider/src/com/android/externalstorage/ExternalStorageProvider.java
@@ -579,6 +579,10 @@
     public AssetFileDescriptor openDocumentThumbnail(
             String documentId, Point sizeHint, CancellationSignal signal)
             throws FileNotFoundException {
+        if (mArchiveHelper.isArchivedDocument(documentId)) {
+            return mArchiveHelper.openDocumentThumbnail(documentId, sizeHint, signal);
+        }
+
         final File file = getFileForDocId(documentId);
         return DocumentsContract.openImageThumbnail(file);
     }