drive: Add showroot=true to WAPI feed URLs and ignore "no parent" entries.

chrome/browser/chromeos/drive/drive_resource_metadata.h

 // 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_DRIVE_DRIVE_RESOURCE_METADATA_H_
 #define CHROME_BROWSER_CHROMEOS_DRIVE_DRIVE_RESOURCE_METADATA_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 34 matching lines @@
   HOSTED_DOCUMENT,
 };
 
 // The root directory name used for the Google Drive file system tree. The
 // name is used in URLs for the file manager, hence user-visible.
 const base::FilePath::CharType kDriveRootDirectory[] =
     FILE_PATH_LITERAL("drive");
 
 // This should be incremented when incompatibility change is made in
 // drive.proto.
-const int32 kProtoVersion = 2;
+const int32 kProtoVersion = 3;

[kinaba, 2013/03/11 09:22:38]

Do we need to trash the old protos at this point?
(In other words, are we storing no parent entries to the disk?)
If not, I think we can postpone the version-up until we're ready to
shared-with-me tab, so that at least existing user data won't
disappear suddenly.

[Haruki Sato, 2013/03/11 14:15:35]

I think yes. They are added to the root, aren't they?
My change just ignores ALL the "no parent" entries.
So without version-up, I guess we will have the issues like 
https://code.google.com/p/chromium/issues/detail?id=127087
again.
I feel like just hide those entries would cause less confusion.

 
 // Callback similar to FileOperationCallback but with a given |file_path|.
 // Used for operations that change a file path like moving files.
 typedef base::Callback<void(DriveFileError error,
                             const base::FilePath& file_path)>
     FileMoveCallback;
 
 // Used to get entry info from the file system.
 // If |error| is not DRIVE_FILE_OK, |entry_info| is set to NULL.
 typedef base::Callback<void(DriveFileError error,
@@ skipping 286 matching lines @@
   // This should remain the last member so it'll be destroyed first and
   // invalidate its weak pointers before other members are destroyed.
   base::WeakPtrFactory<DriveResourceMetadata> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DriveResourceMetadata);
 };
 
 }  // namespace drive
 
 #endif  // CHROME_BROWSER_CHROMEOS_DRIVE_DRIVE_RESOURCE_METADATA_H_