Remove parent* arg from GDataEntry ctor.

* Remove static FromDocumentEntry from GDataEntry, GDataFile, GDataDirectory. Replace with InitFromDocumentEntry.
* Move common code from GDataFile::InitFromDocumentEntry and GDataDirectory::InitFromDocumentEntry to GDataEntry::InitFromDocumentEntry.
* Add GDataDirectoryService::FromDocumentEntry and use this everywhere.
* Make ctors of GDataFile, GDataDirectory private, so these must be created by GDataDirectoryService's CreateGDataFile and
CreateGDataDirectory. Make GDataEntry ctor protected.

BUG=141494
TEST=unit tests.
Review URL: https://chromiumcodereview.appspot.com/10854083

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@151008 0039d316-1c4b-4281-b951-d872f2087c98
void GDataFileSystem::OnRemovedDocument(
    const FileOperationCallback& callback,
    const FilePath& file_path,
    GDataErrorCode status,
    const GURL& document_url) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));

  GDataFileError error = util::GDataToGDataFileError(status);

  if (error == GDATA_FILE_OK)
    error = RemoveEntryFromFileSystem(file_path);

  if (!callback.is_null()) {
    callback.Run(error);
  }
}

void GDataFileSystem::OnRemovedDocument(
    const FileOperationCallback& callback,
    const FilePath& file_path,
    GDataErrorCode status,
    const GURL& document_url) {
  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));

  GDataFileError error = util::GDataToGDataFileError(status);

  if (error == GDATA_FILE_OK)
    error = RemoveEntryFromFileSystem(file_path);

  if (!callback.is_null()) {
    callback.Run(error);
  }
}
