Printing: Push checking of |context| one level lower, as the different
platforms have different expectations at this level.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/3475021

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@60704 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/printing/printing_context_win.cc b/printing/printing_context_win.cc
index a94c71f..83ddfd4 100644
--- a/printing/printing_context_win.cc
+++ b/printing/printing_context_win.cc
@@ -301,6 +301,8 @@
 PrintingContext::Result PrintingContext::NewPage() {
   if (abort_printing_)
     return CANCEL;
+
+  DCHECK(context_);
   DCHECK(in_print_job_);
 
   // Inform the driver that the application is about to begin sending data.