Add updater state for Mac.

components/update_client/updater_state.h

 // Copyright (c) 2016 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 COMPONENTS_UPDATE_CLIENT_UPDATER_STATE_H_
 #define COMPONENTS_UPDATE_CLIENT_UPDATER_STATE_H_
 
 #include <map>
 #include <memory>
 #include <string>
@@ skipping 29 matching lines @@
 
   // Builds the map of state attributes by serializing this object state.
   Attributes BuildAttributes() const;
 
   static std::string GetUpdaterName();
   static base::Version GetUpdaterVersion(bool is_machine);
   static bool IsAutoupdateCheckEnabled();
   static bool IsJoinedToDomain();
   static base::Time GetUpdaterLastStartedAU(bool is_machine);
   static base::Time GetUpdaterLastChecked(bool is_machine);
+#if defined(OS_WIN)

[Sorin Jianu, 2017/05/04 19:53:58]

can we avoid conditional compilation in this file? Can we ignore the is_machine
parameter on macOS?

[borisv, 2017/05/04 22:19:27]

We have to user conditional anyway anyway for the  wchar_t* and char*
difference. I don't believe that Mac knows wchar_t at all. Alternatively, we can
drag an additional header to define it as base::FilePath::CharType. Or we can
try forward declaration of base::FilePath::CharType and then include that header
in updater_state_win.cc. 

A third option (my preference) is that we pull this method out of the class
definition at all. As this is a static method, it can very well be defined
locally for the _win and _mac implementation files. 

[Sorin Jianu, 2017/05/04 22:50:48]

wchar_t is a standard type.

Also, I can change the code to take a char literal, if that is better
accommodated, please tell me which one would you prefer.

   static base::Time GetUpdaterTimeValue(bool is_machine,
                                         const wchar_t* value_name);
+#else
+  static base::Time GetUpdaterTimeValue(const char* value_name);
+#endif
   static int GetUpdatePolicy();
 
   static std::string NormalizeTimeDelta(const base::TimeDelta& delta);
 
   bool is_machine_ = false;
   std::string updater_name_;
   base::Version updater_version_;
   base::Time last_autoupdate_started_;
   base::Time last_checked_;
   bool is_joined_to_domain_ = false;
   bool is_autoupdate_check_enabled_ = false;
   int update_policy_ = 0;
 };
 
 }  // namespace update_client
 
 #endif  // COMPONENTS_UPDATE_CLIENT_UPDATER_STATE_H_