Make ScopedGetDC() CHECK fail if GetDC(NULL) returns NULL.

base/win/scoped_hdc.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_HDC_H_
 #define BASE_WIN_SCOPED_HDC_H_
 #pragma once
 
 #include <windows.h>
 
 #include "base/basictypes.h"
 #include "base/logging.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),
         hdc_(GetDC(hwnd)) {
-    DCHECK(!hwnd_ || IsWindow(hwnd_));
-    DCHECK(hdc_);
+    if (hwnd_) {
+      DCHECK(IsWindow(hwnd_));
+      DCHECK(hdc_);
+    } else {
+      // If GetDC(NULL) returns NULL, something really bad has happened, like
+      // GDI handle exhaustion.  In this case Chrome is going to behave badly no
+      // matter what, so we may as well just force a crash now.
+      CHECK(hdc_);
+    }
   }
 
   ~ScopedGetDC() {
     if (hdc_)
       ReleaseDC(hwnd_, hdc_);
   }
 
   operator HDC() { return hdc_; }
 
  private:
@@ skipping 37 matching lines @@
 
   HDC hdc_;
 
   DISALLOW_COPY_AND_ASSIGN(ScopedCreateDC);
 };
 
 }  // namespace win
 }  // namespace base
 
 #endif  // BASE_WIN_SCOPED_HDC_H_