Fix print media page size by using the value we compute.

chrome/renderer/print_web_view_helper.cc

Index: chrome/renderer/print_web_view_helper.cc
diff --git a/chrome/renderer/print_web_view_helper.cc b/chrome/renderer/print_web_view_helper.cc
index 6cd03b793d38593bc0ba6997fb939bcf316b8f21..27e55c3eeb3f84251757cae24936479463818443 100644
--- a/chrome/renderer/print_web_view_helper.cc
+++ b/chrome/renderer/print_web_view_helper.cc
@@ -1381,8 +1381,6 @@ bool PrintWebViewHelper::PrintPreviewContext::CreatePreviewDocument(
   DCHECK_EQ(INITIALIZED, state_);
   state_ = RENDERING;
 
-  print_params_.reset(new PrintMsg_Print_Params(*print_params));
-
   metafile_.reset(new printing::PreviewMetafile);
   if (!metafile_->Init()) {
     set_error(PREVIEW_ERROR_METAFILE_INIT_FAILED);
@@ -1396,6 +1394,8 @@ bool PrintWebViewHelper::PrintPreviewContext::CreatePreviewDocument(
   UpdatePrintableSizeInPrintParameters(frame_, node_,
                                        prep_frame_view_.get(), print_params);
 
+  print_params_.reset(new PrintMsg_Print_Params(*print_params));
+
   total_page_count_ = prep_frame_view_->GetExpectedPageCount();
   if (total_page_count_ == 0) {
     LOG(ERROR) << "CreatePreviewDocument got 0 page count";