mediaview: Mount ARC documents provider file system volumes.

chrome/browser/chromeos/arc/fileapi/arc_media_view_util.cc

+// Copyright 2017 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.
+
+#include "chrome/browser/chromeos/arc/fileapi/arc_media_view_util.h"
+
+namespace arc {
+
+namespace {
+
+constexpr char kMediaViewVolumeIdPrefix[] = "media_view:";
+
+}  // namespace
+
+const base::Feature kMediaViewFeature{"ArcMediaView",
+                                      base::FEATURE_DISABLED_BY_DEFAULT};
+
+const char kMediaDocumentsProviderAuthority[] =
+    "com.android.providers.media.documents";
+
+const char kImagesRootDocumentId[] = "images_root";
+const char kVideosRootDocumentId[] = "videos_root";
+const char kAudioRootDocumentId[] = "audio_root";
+
+std::string GetMediaViewVolumeId(const std::string& root_document_id) {
+  return std::string(kMediaViewVolumeIdPrefix) + root_document_id;
+}
+
+}  // namespace arc