Make GetUserName() return more specific error code, so that we could know how the function failed.

rlz/win/lib/process_info.cc

 // 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.
 //
 // Information about the current process.
 
 #include "rlz/win/lib/process_info.h"
 
 #include <windows.h>
 #include <Sddl.h>  // For ConvertSidToStringSid.
@@ skipping 15 matching lines @@
 
   // Get the current username & domain the hard way.  (GetUserNameEx would be
   // nice, but unfortunately requires connectivity to a domain controller.
   // Useless.)
 
   // (Following call doesn't work if running as a Service - because a Service
   // runs under special accounts like LOCAL_SYSTEM, not as the logged in user.
   // In which case, search for and use the process handle of a running
   // Explorer.exe.)
   HANDLE token;
-  if (!::OpenProcessToken(::GetCurrentProcess(), TOKEN_QUERY, &token))
-    return E_FAIL;
+
+  HANDLE process_handle = ::GetCurrentProcess()
+  if (!process_handle)
+    CHECK(0)

[jar (doing other things), 2014/02/26 00:27:08]

Please try to compile code before sending for a review.

Please put semicolons at end of each line of code.

Don't bother doing anything else once you hit a "CHECK".

Perhaps clearer would be:
CHECK_NE(process_handle, 0);

+    return ::GetLastError()

[jar (doing other things), 2014/02/26 00:27:08]

Note that IF you used a semicolon (on line 39), since this is NOT Python, you
would run the return statement all the time, and never reach line 42.

+
+  if (!::OpenProcessToken(process_handle, TOKEN_QUERY, &token))
+    CHECK(0)
+    return ::GetLastError()
 
   base::win::ScopedHandle scoped_process_token(token);
 
   // (Following call will fail with ERROR_INSUFFICIENT_BUFFER and give us the
   // required size.)
   scoped_ptr<char[]> token_user_bytes;
   DWORD token_user_size;
   DWORD token_user_size2;
   BOOL result = ::GetTokenInformation(token, TokenUser, NULL, 0,
                                       &token_user_size);
   err = ::GetLastError();
   CHECK(!result && err == ERROR_INSUFFICIENT_BUFFER);
 
   token_user_bytes.reset(new char[token_user_size]);
   if (!token_user_bytes.get())
+    CHECK(0)
     return E_OUTOFMEMORY;
 
   if (!::GetTokenInformation(token, TokenUser, token_user_bytes.get(),
                              token_user_size, &token_user_size2)) {
-    return E_FAIL;
+    CHECK(0)
+    return ::GetLastError();
   }
 
   WCHAR user_name[UNLEN + 1];  // max username length
   WCHAR domain_name[UNLEN + 1];
   DWORD user_name_size = UNLEN + 1;
   DWORD domain_name_size = UNLEN + 1;
   SID_NAME_USE sid_type;
   TOKEN_USER* token_user =
       reinterpret_cast<TOKEN_USER*>(token_user_bytes.get());
   if (!token_user)
-    return E_FAIL;
+    CHECK(0)
+    return ::GetLastError();
   PSID user_sid = token_user->User.Sid;
   if (!::LookupAccountSidW(NULL, user_sid, user_name, &user_name_size,
                            domain_name, &domain_name_size, &sid_type)) {
-    return E_FAIL;
+    CHECK(0)
+    return ::GetLastError();
   }
 
   if (name != NULL) {
     *name = user_name;
   }
   if (domain != NULL) {
     *domain = domain_name;
   }
   if (sid != NULL) {
     LPWSTR string_sid;
@@ skipping 103 matching lines @@
   }
 
   evaluated = true;
   if (!has_rights)
     ASSERT_STRING("ProcessInfo::HasAdminRights: Does not have admin rights.");
 
   return has_rights;
 }
 
 };  // namespace