Added base::win::InitializeWindowClass() wrapper to make sure that window classes are properly asso…

base/win/wrapped_window_proc.cc

 // 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.
 
 #include "base/win/wrapped_window_proc.h"
 
 #include "base/atomicops.h"
+#include "base/logging.h"
+#include "base/process_util.h"
 
 namespace {
 
 base::win::WinProcExceptionFilter s_exception_filter = NULL;
 
 }  // namespace.
 
 namespace base {
 namespace win {
 
 WinProcExceptionFilter SetWinProcExceptionFilter(
     WinProcExceptionFilter filter) {
   subtle::AtomicWord rv = subtle::NoBarrier_AtomicExchange(
       reinterpret_cast<subtle::AtomicWord*>(&s_exception_filter),
       reinterpret_cast<subtle::AtomicWord>(filter));
   return reinterpret_cast<WinProcExceptionFilter>(rv);
 }
 
 int CallExceptionFilter(EXCEPTION_POINTERS* info) {
   return s_exception_filter ? s_exception_filter(info) :
                               EXCEPTION_CONTINUE_SEARCH;
 }
 
+BASE_EXPORT void InitializeWindowClass(
+    const char16* class_name,
+    WNDPROC window_proc,
+    UINT style,
+    int class_extra,
+    int window_extra,
+    HCURSOR cursor,
+    HBRUSH background,
+    const char16* menu_name,
+    HICON large_icon,
+    HICON small_icon,
+    WNDCLASSEX* class_out) {
+  class_out->cbSize = sizeof(WNDCLASSEX);

[dcheng, 2012/05/04 19:40:31]

Should we add a compile assert here so we don't forget to initialize members
that get added?

[alexeypa (please no reviews), 2012/05/04 19:54:24]

WNDCLASSEX is a public API. It is set in stone and never changes.

It is possible however that a new structure extending WNDCLASSEX will be
introduced in the future (and say cbSize will be tested to see which structure
is passes to Win32 APIs). In such a case this function will support only the old
WNDCLASSEX structure, so it will be up to the extender of INitializeWindowClass
to take care of choosing between the old and new WNDCLASSEX.

[brettw, 2012/05/04 20:00:55]

I agree with no assert here.

+  class_out->style = style;
+  class_out->lpfnWndProc = window_proc;
+  class_out->cbClsExtra = class_extra;
+  class_out->cbWndExtra = window_extra;
+  class_out->hInstance = base::GetModuleFromAddress(window_proc);
+  class_out->hIcon = large_icon;
+  class_out->hCursor = cursor;
+  class_out->hbrBackground = background;
+  class_out->lpszMenuName = menu_name;
+  class_out->lpszClassName = class_name;
+  class_out->hIconSm = small_icon;
+
+  // Check if |window_proc| is valid.
+  DCHECK(class_out->hInstance != NULL);
+}
+
 }  // namespace win
 }  // namespace base