You can now add a full featured native PDF viewer for Iconic & Cordova mobile apps. PDFTron’s plugin lets you open PDFs in a native viewer directly from the device or from a web server. In addition it supports MS Office documents and has built-in annotation tools. Read blog post
Getting started:
Full details can be found on the Ionic / Cordova PDF Viewer Github page.
A sample project that uses the plugin is also available on Github.