We are upgrading the chromium browser from 118.0.5993.117 to 126.0.6478.126 for our embedded system. For PDF extension, we are migrating the PDF feature from chrome/browser to content/shell where the interfaces are exposed to the applications.

We moved the PDF feature from chrome/browser to content/shell successfully in 118.0.5993.117.

But in 126.0.6478.126, we are not able to do it because of new features like pdfViewerPrivate and OOPIF. So, we tried to fall back to old implementation as in 118.0.5993.117 where mimeHandlerPrivate feature is used to load the PDF page. For that, we have disabled pdfViewerPrivate and OOPIF features. Also, enabled ENABLE_PPAPI flag.

But we are getting the following error:

[ERROR:extension_function_dispatcher(641)] Unknown Extension API - mimeHandlerPrivate.getStreamInfo

Also, during the debugging we found the BindMimeHandlerService is not called, even after registering this function correctly. This is also the main reason for PDF page load failure.

How to debug why BindMimeHandlerService function is not being called? Any leads in this regard, will be very useful.

Thanks in advance.