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

base/win/windows_version.h

Index: base/win/windows_version.h
diff --git a/base/win/windows_version.h b/base/win/windows_version.h
index 676bd979578b9fc07b83bed55d6d5257650858c8..67e7d6840c4d136b44a536714b0763ff4ec70c77 100644
--- a/base/win/windows_version.h
+++ b/base/win/windows_version.h
@@ -86,6 +86,7 @@ class BASE_EXPORT OSInfo {
   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_; }
@@ -105,6 +106,8 @@ class BASE_EXPORT OSInfo {
   ~OSInfo();
 
   Version version_;
+  mutable Version kernel32_version_;
+  mutable bool got_kernel32_version_;
   VersionNumber version_number_;
   VersionType version_type_;
   ServicePack service_pack_;