Use GenericScopedHandle to implement ScopedCreateDC.

base/win/scoped_hdc.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_SCOPED_HDC_H_
 #define BASE_WIN_SCOPED_HDC_H_
 #pragma once
 
 #include <windows.h>
 
 #include "base/basictypes.h"
 #include "base/logging.h"
+#include "base/win/scoped_handle.h"
 
 namespace base {
 namespace win {
 
 // Like ScopedHandle but for HDC.  Only use this on HDCs returned from
 // GetDC.
 class ScopedGetDC {
  public:
   explicit ScopedGetDC(HWND hwnd)
       : hwnd_(hwnd),
@@ skipping 18 matching lines @@
 
  private:
   HWND hwnd_;
   HDC hdc_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedGetDC);
 };
 
 // Like ScopedHandle but for HDC.  Only use this on HDCs returned from
 // CreateCompatibleDC, CreateDC and CreateIC.
-class ScopedCreateDC {
+class CreateDCTraits {
  public:
-  ScopedCreateDC() : hdc_(NULL) { }
-  explicit ScopedCreateDC(HDC h) : hdc_(h) { }
+  typedef HDC Handle;
 
-  ~ScopedCreateDC() {
-    Close();
+  static bool CloseHandle(HDC handle) {
+    return ::DeleteDC(handle) != FALSE;
   }
 
-  HDC Get() {
-    return hdc_;
+  static bool IsHandleValid(HDC handle) {
+    return handle != NULL;
   }
 
-  void Set(HDC h) {
-    Close();
-    hdc_ = h;
+  static HDC NullHandle() {
+    return NULL;
   }
 
-  operator HDC() { return hdc_; }
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(CreateDCTraits);
+};
 
- private:
-  void Close() {
-#ifdef NOGDI

[alexeypa (please no reviews), 2012/07/12 18:18:00]

This code was wrong BTW. When NOGDI is defined DeleteDC() should not be
declared. So it should not compile which is correct behavior.

Potentially this might be a problem if there is a code that depends
ScopedCreateDC compiled with NOGDI defined. What out for compilation issues on
the bots.

-    assert(false);
-#else
-    if (hdc_)
-      DeleteDC(hdc_);
-#endif  // NOGDI
-  }
-
-  HDC hdc_;
-
-  DISALLOW_COPY_AND_ASSIGN(ScopedCreateDC);
-};
+typedef GenericScopedHandle<CreateDCTraits, VerifierTraits> ScopedCreateDC;
 
 }  // namespace win
 }  // namespace base
 
 #endif  // BASE_WIN_SCOPED_HDC_H_