Support MTA as well in the scoped COM initializer.

base/win/scoped_com_initializer.h

 // Copyright (c) 2011 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_SCOPED_COM_INITIALIZER_H_
 #define BASE_WIN_SCOPED_COM_INITIALIZER_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
 
 #include <objbase.h>
 
 namespace base {
 namespace win {
 
-// Initializes COM in the constructor (STA), and uninitializes COM in the
+// Initializes COM in the constructor (STA or MTA), and uninitializes COM in the
 // destructor.
 class ScopedCOMInitializer {
  public:
+  // Enum value provided to initialize the thread as an MTA instead of STA.
+  enum SelectMTA { kMTA };
+
+  // Constructor for STA initialization.
   ScopedCOMInitializer() : hr_(CoInitialize(NULL)) {
   }
 
+  // Constructor for MTA initialization.
+  explicit ScopedCOMInitializer(SelectMTA mta)
+    : hr_(CoInitializeEx(NULL, COINIT_MULTITHREADED)) {
+  }
+
   ScopedCOMInitializer::~ScopedCOMInitializer() {
     if (SUCCEEDED(hr_))
       CoUninitialize();
   }
 
+  bool succeeded() const { return SUCCEEDED(hr_); }
+
  private:
   HRESULT hr_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedCOMInitializer);
 };
 
 }  // namespace win
 }  // namespace base
 
 #else
 
 namespace base {
 namespace win {
 
 // Do-nothing class for other platforms.
 class ScopedCOMInitializer {
  public:
+  enum SelectMTA { kMTA };
   ScopedCOMInitializer() {}
+  explicit ScopedCOMInitializer(SelectMTA mta) {}
   ~ScopedCOMInitializer() {}
 
+  bool succeeded() const { return true; }
+
  private:
   DISALLOW_COPY_AND_ASSIGN(ScopedCOMInitializer);
 };
 
 }  // namespace win
 }  // namespace base
 
 #endif
 
 #endif  // BASE_WIN_SCOPED_COM_INITIALIZER_H_