Revert of Add SingleLogSource to system_logs sources

chrome/browser/chromeos/system_logs/single_log_source.h

-// 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.
-
-#ifndef CHROME_BROWSER_CHROMEOS_SYSTEM_LOGS_SINGLE_LOG_SOURCE_H_
-#define CHROME_BROWSER_CHROMEOS_SYSTEM_LOGS_SINGLE_LOG_SOURCE_H_
-
-#include <stddef.h>
-
-#include "base/files/file.h"
-#include "base/macros.h"
-#include "chrome/browser/feedback/system_logs/system_logs_fetcher_base.h"
-#include "components/feedback/anonymizer_tool.h"
-
-namespace system_logs {
-
-// Gathers log data from a single source, possibly incrementally.
-class SingleLogSource : public SystemLogsSource {
- public:
-  enum class SupportedSource {
-    // For /var/log/messages.
-    kMessages,
-
-    // For /var/log/ui/ui.LATEST.
-    kUiLatest,
-  };
-
-  explicit SingleLogSource(SupportedSource source);
-  ~SingleLogSource() override;
-
-  // system_logs::SystemLogsSource:
-  void Fetch(const SysLogsSourceCallback& callback) override;
-
- private:
-  friend class SingleLogSourceTest;
-
-  // Reads all available content from |file_| that has not already been read.
-  void ReadFile(SystemLogsResponse* result);
-
-  // Keeps track of how much data has been read from |file_|.
-  size_t num_bytes_read_;
-
-  // Handle for reading the log file that is source of logging data.
-  base::File file_;
-
-  // For removing PII from log results.
-  feedback::AnonymizerTool anonymizer_;
-
-  base::WeakPtrFactory<SingleLogSource> weak_ptr_factory_;
-
-  DISALLOW_COPY_AND_ASSIGN(SingleLogSource);
-};
-
-}  // namespace system_logs
-
-#endif  // CHROME_BROWSER_CHROMEOS_SYSTEM_LOGS_SINGLE_LOG_SOURCE_H_