Printing: Push checking of |context| one level lower, as the different

printing/printed_document_win.cc

 // Copyright (c) 2009 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 "printing/printed_document.h"
 
 #include "base/logging.h"
 #include "base/string_util.h"
 #include "gfx/font.h"
 #include "printing/page_number.h"
@@ skipping 30 matching lines @@
 void PrintedDocument::RenderPrintedPage(
     const PrintedPage& page, gfx::NativeDrawingContext context) const {
 #ifndef NDEBUG
   {
     // Make sure the page is from our list.
     AutoLock lock(lock_);
     DCHECK(&page == mutable_.pages_.find(page.page_number() - 1)->second.get());
   }
 #endif
 
+  DCHECK(context);
+
   const printing::PageSetup& page_setup(
       immutable_.settings_.page_setup_device_units());
   gfx::Rect content_area;
   page.GetCenteredPageContentRect(page_setup.physical_size(), &content_area);
 
   // Save the state to make sure the context this function call does not modify
   // the device context.
   int saved_state = SaveDC(context);
   DCHECK_NE(saved_state, 0);
   skia::PlatformDevice::InitializeDC(context);
@@ skipping 73 matching lines @@
                     font);
   PrintHeaderFooter(context, page, PageOverlays::CENTER, PageOverlays::BOTTOM,
                     font);
   PrintHeaderFooter(context, page, PageOverlays::RIGHT, PageOverlays::BOTTOM,
                     font);
   int res = RestoreDC(context, saved_state);
   DCHECK_NE(res, 0);
 }
 
 }  // namespace printing