[Media Gallery] Added code to support mtp device media file system on Windows.

chrome/browser/media_gallery/win/mtp_device_object_enumerator.cc

+// Copyright (c) 2013 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.
+//
+// MTPDeviceObjectEnumerator implementation.
+
+#include "chrome/browser/media_gallery/win/mtp_device_object_enumerator.h"
+
+#include "base/threading/thread_restrictions.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace chrome {
+
+MTPDeviceObjectEnumerator::MTPDeviceObjectEnumerator(
+    const MTPDeviceObjectEntries& entries)
+    : object_entries_(entries),
+      object_entry_iter_(object_entries_.begin()),
+      current_object_(NULL) {
+  base::ThreadRestrictions::AssertIOAllowed();
+}
+
+MTPDeviceObjectEnumerator::~MTPDeviceObjectEnumerator() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+}
+
+FilePath MTPDeviceObjectEnumerator::Next() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if (object_entry_iter_ == object_entries_.end()) {
+    current_object_ = NULL;
+    return FilePath();
+  }
+
+  current_object_ = &(*(object_entry_iter_++));
+  return FilePath(current_object_->name);
+}
+
+int64 MTPDeviceObjectEnumerator::Size() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  return current_object_ ? current_object_->size : 0;
+}
+
+bool MTPDeviceObjectEnumerator::IsDirectory() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  return current_object_ ? current_object_->is_directory : false;
+}
+
+base::Time MTPDeviceObjectEnumerator::LastModifiedTime() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  return current_object_ ? current_object_->last_modified_time : base::Time();
+}
+
+}  // namespace chrome