Created min size for print preview dialog and modified to allow the

chrome/browser/printing/print_preview_dialog_controller.h

Index: chrome/browser/printing/print_preview_dialog_controller.h
diff --git a/chrome/browser/printing/print_preview_dialog_controller.h b/chrome/browser/printing/print_preview_dialog_controller.h
index 85e9880a44453125c8437dc918e11b778748c516..5e7dc44357a844e41a810625b50423a5a8fee88e 100644
--- a/chrome/browser/printing/print_preview_dialog_controller.h
+++ b/chrome/browser/printing/print_preview_dialog_controller.h
@@ -10,9 +10,11 @@
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
+#include "chrome/browser/ui/webui/constrained_web_dialog_ui.h"
 #include "components/sessions/core/session_id.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
+#include "ui/web_dialogs/web_dialog_delegate.h"
 
 class GURL;
 
@@ -23,6 +25,8 @@ class WebContents;
 }
 
 namespace printing {
+  ui::WebDialogDelegate * GetPrintPreviewDialogDelegate(
+      content::WebContents * initiator);
 
 // For print preview, the WebContents that initiates the printing operation is
 // the initiator, and the constrained dialog that shows the print preview is the
@@ -78,6 +82,11 @@ class PrintPreviewDialogController
   bool is_creating_print_preview_dialog() const {
     return is_creating_print_preview_dialog_;
   }
+ protected:
+  ~PrintPreviewDialogController() override;
+
+  virtual ConstrainedWebDialogDelegate * GetWebDialogDelegate(
+      content::WebContents* initiator);
 
  private:
   friend class base::RefCounted<PrintPreviewDialogController>;
@@ -88,8 +97,6 @@ class PrintPreviewDialogController
   using PrintPreviewDialogMap =
       std::map<content::WebContents*, content::WebContents*>;
 
-  ~PrintPreviewDialogController() override;
-
   // Handler for the RENDERER_PROCESS_CLOSED notification. This is observed when
   // the initiator renderer crashed.
   void OnRendererProcessClosed(content::RenderProcessHost* rph);