drive: Deal with the root directory in the same way as others in MoveOperation.

chrome/browser/google_apis/fake_drive_service.cc

 // Copyright (c) 2012 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/google_apis/fake_drive_service.h"
 
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/string_number_conversions.h"
@@ skipping 560 matching lines @@
             link->GetString("href", &href) &&
             rel == "http://schemas.google.com/docs/2007#parent" &&
             GURL(href) == parent_content_url) {
           links->Remove(i, NULL);
           AddNewChangestamp(entry);
           MessageLoop::current()->PostTask(
               FROM_HERE, base::Bind(callback, HTTP_SUCCESS));
           return;
         }
       }
+
+      // We are dealing with a no-"parent"-link file as in the root directory.
+      if (parent_content_url.is_empty()) {
+        AddNewChangestamp(entry);
+        MessageLoop::current()->PostTask(
+            FROM_HERE, base::Bind(callback, HTTP_SUCCESS));
+        return;
+      }
     }
   }
 
   MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(callback, HTTP_NOT_FOUND));
 }
 
 void FakeDriveService::AddNewDirectory(
     const GURL& parent_content_url,
     const FilePath::StringType& directory_name,
@@ skipping 195 matching lines @@
   return base::StringPrintf("resource_id_%d", resource_id_count_);
 }
 
 void FakeDriveService::AddNewChangestamp(base::DictionaryValue* entry) {
   ++largest_changestamp_;
   entry->SetString("docs$changestamp.value",
                    base::Int64ToString(largest_changestamp_));
 }
 
 }  // namespace google_apis