This is interesting. Mozilla is working on a new Project Mortar, which aims to explore the possibility of bringing PDFium (Google Chrome PDF rendering engine, which is now open sourced) library and Pepper API based Flash plugin into the Firefox browser. The team behind the project is working on creating a new public repository to track the work.

As of now, they’ve integrated Firefox with PDFium and enabled basic PDF rendering functionalities. The team is planning to complete the basic PDF viewer functionalities by the end of 2016, and have set implementing advanced PDF viewer features such as save document, print and form submission as goals for 2017 H1. When the project is completed, most likely to ship to Firefox release channel in the form of a system add-on, but it’s yet to be determined.

READ: Opera integrates Chrome PDF Viewer into the developer Stream

Mortar Project

UPDATE: This is what Mozilla’s Johnny Stenback  said about the project.

“The project will start by investigating how Firefox handles PDF rendering followed by looking into lower cost approaches to providing
Flash support as it’s usage continues to decrease. Project Mortar is currently investigating using the minimum set of Pepper APIs needed to support the PDFium library and the Pepper Flash plugin. If successful, this work will allow us to completely remove NPAPI support from Firefox once NPAPI is disabled for general plugin use. ”

Read Mozilla announcement on Project Mortar here.