__FUNCTION__ cannot concatenate with constant strings in all compilers.

win8/test/ui_automation_client.cc

 // Copyright (c) 2013 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.
 
 #include "win8/test/ui_automation_client.h"
 
 #include <atlbase.h>
 #include <atlcom.h>
 #include <oleauto.h>
 #include <uiautomation.h>
@@ skipping 303 matching lines @@
   base::win::ScopedVariant var;
 
   hr = window->GetCachedPropertyValueEx(UIA_ClassNamePropertyId, TRUE,
                                         var.Receive());
   if (FAILED(hr)) {
     LOG(ERROR) << std::hex << hr;
     return;
   }
 
   if (V_VT(&var) != VT_BSTR) {
-    LOG(ERROR) << __FUNCTION__ " class name is not a BSTR: " << V_VT(&var);
+    LOG(ERROR) << __FUNCTION__ << " class name is not a BSTR: " << V_VT(&var);
     return;
   }
 
   base::string16 class_name(V_BSTR(&var));
 
   // Window class names are atoms, which are case-insensitive.
   if (class_name.size() == class_name_.size() &&
       std::equal(class_name.begin(), class_name.end(), class_name_.begin(),
                  base::CaseInsensitiveCompare<wchar_t>())) {
     RemoveWindowObserver();
@@ skipping 283 matching lines @@
                  context_,
                  base::ThreadTaskRunnerHandle::Get(),
                  base::string16(class_name),
                  item_name,
                  init_callback,
                  result_callback));
 }
 
 }  // namespace internal
 }  // namespace win8