diff --git content/browser/web_contents/web_contents_view.h content/browser/web_contents/web_contents_view.h
index 285dc38950991..326646bb585da 100644
--- content/browser/web_contents/web_contents_view.h
+++ content/browser/web_contents/web_contents_view.h
@@ -26,7 +26,7 @@ struct DropData;
 // The `WebContentsView` is an interface that is implemented by the platform-
 // dependent web contents views. The `WebContents` uses this interface to talk
 // to them.
-class WebContentsView {
+class CONTENT_EXPORT WebContentsView {
  public:
   virtual ~WebContentsView() = default;
 
diff --git extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.cc extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.cc
index bd8b5ddfd8659..767c0ec89ef7a 100644
--- extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.cc
+++ extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest.cc
@@ -205,6 +205,8 @@ void MimeHandlerViewGuest::CreateWebContents(
   WebContents::CreateParams params(browser_context(),
                                    guest_site_instance.get());
   params.guest_delegate = this;
+  if (delegate_)
+    delegate_->OverrideWebContentsCreateParams(&params);
   std::move(callback).Run(std::move(owned_this),
                           WebContents::CreateWithSessionStorage(
                               params, owner_web_contents()
diff --git extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest_delegate.h extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest_delegate.h
index 7f59e7925084e..e3e69dc6d3a43 100644
--- extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest_delegate.h
+++ extensions/browser/guest_view/mime_handler_view/mime_handler_view_guest_delegate.h
@@ -7,6 +7,8 @@
 
 #include <string>
 
+#include "content/public/browser/web_contents.h"
+
 namespace content {
 class RenderFrameHost;
 struct ContextMenuParams;
@@ -25,6 +27,10 @@ class MimeHandlerViewGuestDelegate {
 
   virtual ~MimeHandlerViewGuestDelegate() {}
 
+  // Provides an opportunity to supply a custom view implementation.
+  virtual void OverrideWebContentsCreateParams(
+      content::WebContents::CreateParams* params) {}
+
   // Handles context menu, or returns false if unhandled.
   //
   // The `render_frame_host` represents the frame that requests the context menu