Force MimeHandlerView to always use BrowserPlugin

content/browser/frame_host/render_widget_host_view_guest.cc

Index: content/browser/frame_host/render_widget_host_view_guest.cc
diff --git a/content/browser/frame_host/render_widget_host_view_guest.cc b/content/browser/frame_host/render_widget_host_view_guest.cc
index d433e64c164122f7deae254bb6a39da4f45014db..634fa9af97fce484a86a6ae081d189667cd7347b 100644
--- a/content/browser/frame_host/render_widget_host_view_guest.cc
+++ b/content/browser/frame_host/render_widget_host_view_guest.cc
@@ -353,9 +353,13 @@ gfx::NativeView RenderWidgetHostViewGuest::GetNativeView() const {
   if (!guest_)
     return gfx::NativeView();
 
-  RenderWidgetHostView* rwhv = guest_->GetOwnerRenderWidgetHostView();
+  if (guest_->IsMimeHandlerViewGuest())
+    return guest_->GetTopLevelRenderWidgetHostView()->GetNativeView();

[EhsanK, 2016/07/19 21:48:44]

To be precise, I should also add UseCrossProcessFramesForGuest in the if
condition. But I think we can simply only return top-level native view instead,
given that the old logic was to return the owner's anyway.

+
+  RenderWidgetHostView* rwhv = GetOwnerRenderWidgetHostView();
   if (!rwhv)
     return gfx::NativeView();
+
   return rwhv->GetNativeView();
 }