Bug 1074051 - [Settings] sound volume is not changed. Patch v2.0
Merge pull request #25608 from mancas/bug1074051_v2.0

Bug 1074051 - [Settings] sound volume is not changed. Patch v2.0
Bug 1069157 - [PDF Viewer] update pdf.js in Gaia

Conflicts:
	apps/pdfjs/content/build/pdf.js
	apps/pdfjs/content/build/pdf.worker.js
	apps/pdfjs/content/web/viewer.html
	apps/pdfjs/content/web/viewer.js
Revert "Bug 1069157 - [PDF Viewer] update pdf.js in Gaia"

This reverts commit 414f2ff5c7d000e151b970df3871f63082e4a300.
Merge branch 'v2.0' into v2.0m