Address some additional cleanup work needed for the component flash updates on Linux.

chrome/common/component_flash_hint_file_linux.h

 // Copyright 2015 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_COMMON_COMPONENT_FLASH_HINT_FILE_LINUX_H_
 #define CHROME_COMMON_COMPONENT_FLASH_HINT_FILE_LINUX_H_
 
 #include "build/build_config.h"
 
-#if defined(OS_LINUX)
+#if !defined(OS_LINUX)
+#error "This file only applies to the Linux component update of Flash."
+#endif  // !defined(OS_LINUX)
 
 #include <string>
 
 namespace base {
 class FilePath;
 }
 
-namespace chrome {
-
 // The APIs in this namespace wraps the component updated flash hint file, which
 // lives inside the PepperFlash folder of  the user-data-dir, so that the Linux
 // zygote process can preload the right version of flash.
 namespace component_flash_hint_file {
 
 // Records a new flash update into the hint file.
 // |unpacked_plugin| is the current location of the plugin.
 // |moved_plugin| is the location where the plugin will be loaded from.
 bool RecordFlashUpdate(const base::FilePath& unpacked_plugin,
                        const base::FilePath& moved_plugin,
                        const std::string& version);
 
 // Reports whether or not a hints file exists.
 bool DoesHintFileExist();
 
 // Return the path of the component updated flash plugin, only if the file has
 // the correct hash sum.
 // |path| will be populated with the path to the flash plugin.
 // |version| will be populated with the version of the flash plugin.
 bool VerifyAndReturnFlashLocation(base::FilePath* path, std::string* version);
 
 // Test if the specified plugin file can be mapped executable.
 // This is useful to test if the flash plugin is in a directory mounted
 // noexec, in which case Chrome will not be able to load and use the plugin.
 // |path| is the path of the flash plugin that will mapped executable.
 bool TestExecutableMapping(const base::FilePath& path);
 
 }  // namespace component_flash_hint_file
 
-}  // namespace chrome
-
-#endif  // defined(OS_LINUX)
 #endif  // CHROME_COMMON_COMPONENT_FLASH_HINT_FILE_LINUX_H_