Add histograms to compare GetVersionEx() with VerQueryValue() of kernel32

base/win/windows_version.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 BASE_WIN_WINDOWS_VERSION_H_
 #define BASE_WIN_WINDOWS_VERSION_H_
 
 #include <stddef.h>
 
 #include <string>
 
 #include "base/base_export.h"
 #include "base/macros.h"
 
 typedef void* HANDLE;
 
 namespace base {
 namespace win {
 
 // The running version of Windows.  This is declared outside OSInfo for
-// syntactic sugar reasons; see the declaration of GetVersion() below.
-// NOTE: Keep these in order so callers can do things like
-// "if (base::win::GetVersion() >= base::win::VERSION_VISTA) ...".
+// syntactic sugar reasons; see the declaration of GetVersion() below. NOTE:

[robliao, 2016/03/11 17:04:47]

Nit: This NOTE should probably still remain on the next line.

[scottmg, 2016/03/11 22:44:26]

Done.

+// Keep these in order so callers can do things like "if

[robliao, 2016/03/11 17:04:47]

"if 
should be on the next line.

[scottmg, 2016/03/11 22:44:26]

Done.

+// (base::win::GetVersion() >= base::win::VERSION_VISTA) ...".
+//
+// This enum is used in metrics histograms, so they shouldn't be reordered or
+// removed. New values can be added before VERSION_WIN_LAST.
 enum Version {
   VERSION_PRE_XP = 0,  // Not supported.
-  VERSION_XP,
-  VERSION_SERVER_2003,  // Also includes XP Pro x64 and Server 2003 R2.
-  VERSION_VISTA,        // Also includes Windows Server 2008.
-  VERSION_WIN7,         // Also includes Windows Server 2008 R2.
-  VERSION_WIN8,         // Also includes Windows Server 2012.
-  VERSION_WIN8_1,       // Also includes Windows Server 2012 R2.
-  VERSION_WIN10,        // Also includes Windows 10 Server.
-  VERSION_WIN10_TH2,    // Threshold 2: Version 1511, Build 10586.
-  VERSION_WIN_LAST,     // Indicates error condition.
+  VERSION_XP = 1,
+  VERSION_SERVER_2003 = 2,  // Also includes XP Pro x64 and Server 2003 R2.
+  VERSION_VISTA = 3,        // Also includes Windows Server 2008.
+  VERSION_WIN7 = 4,         // Also includes Windows Server 2008 R2.
+  VERSION_WIN8 = 5,         // Also includes Windows Server 2012.
+  VERSION_WIN8_1 = 6,       // Also includes Windows Server 2012 R2.
+  VERSION_WIN10 = 7,        // Also includes Windows 10 Server.
+  VERSION_WIN10_TH2 = 8,    // Threshold 2: Version 1511, Build 10586.
+  VERSION_WIN_LAST,         // Indicates error condition.
 };
 
 // A rough bucketing of the available types of versions of Windows. This is used
 // to distinguish enterprise enabled versions from home versions and potentially
 // server versions.
 enum VersionType {
   SUITE_HOME,
   SUITE_PROFESSIONAL,
   SUITE_SERVER,
   SUITE_LAST,
@@ skipping 34 matching lines @@
   // the process does not have sufficient access rights to determine this.
   enum WOW64Status {
     WOW64_DISABLED,
     WOW64_ENABLED,
     WOW64_UNKNOWN,
   };
 
   static OSInfo* GetInstance();
 
   Version version() const { return version_; }
+  Version Kernel32Version() const;
   // The next two functions return arrays of values, [major, minor(, build)].
   VersionNumber version_number() const { return version_number_; }
   VersionType version_type() const { return version_type_; }
   ServicePack service_pack() const { return service_pack_; }
   WindowsArchitecture architecture() const { return architecture_; }
   int processors() const { return processors_; }
   size_t allocation_granularity() const { return allocation_granularity_; }
   WOW64Status wow64_status() const { return wow64_status_; }
   std::string processor_model_name();
 
   // Like wow64_status(), but for the supplied handle instead of the current
   // process.  This doesn't touch member state, so you can bypass the singleton.
   static WOW64Status GetWOW64StatusForProcess(HANDLE process_handle);
 
  private:
   OSInfo();
   ~OSInfo();
 
   Version version_;
+  mutable Version kernel32_version_;
+  mutable bool got_kernel32_version_;
   VersionNumber version_number_;
   VersionType version_type_;
   ServicePack service_pack_;
   WindowsArchitecture architecture_;
   int processors_;
   size_t allocation_granularity_;
   WOW64Status wow64_status_;
   std::string processor_model_name_;
 
   DISALLOW_COPY_AND_ASSIGN(OSInfo);
 };
 
 // Because this is by far the most commonly-requested value from the above
 // singleton, we add a global-scope accessor here as syntactic sugar.
 BASE_EXPORT Version GetVersion();
 
 }  // namespace win
 }  // namespace base
 
 #endif  // BASE_WIN_WINDOWS_VERSION_H_