Bug 1664459 R[Core:Graphics: WebRender]Simplify WebRender radial gradient shader
Bug 1664703 R[Core:Graphics: WebRender]Cover more cases where we need a reason for WebRender initialization failures (again)
Bug 1664156 R[Core:Layout: Images, Video, and HTML Frames]CSP-blocked images have `display: none !important` UA style
Bug 1658121 R[Core:MathML]Implement padding/border layout for <mspace>
Bug 1655130 R[Core:Panning and Zooming][Regression] Can't disable smooth scrolling
Bug 1658169 R[Core:Panning and Zooming]apz side smooth scroll physics is different from main thread
Bug 1661903 R[Core:Panning and Zooming]Make behaviour for scrollBy(0, 0) consistent while APZ scroll animation is in progress
Bug 1662013 R[Core:Panning and Zooming]Make the scroll updates sent from the main thread to APZ easier to understand and debug
Bug 1662014 R[Core:Panning and Zooming]Delete unused codepaths for scroll update propagation
Bug 1663537 A[Core:Panning and Zooming]fix tests to handle desktop zooming scrollbars
Bug 1662477 R[Firefox:Address Bar]Don't toggle local one-offs if urlbar privacy preferences are flipped
Bug 1663879 R[Firefox:General]pdf.js shows a domain of "pdf.js" when going fullscreen
Bug 863474 A[Firefox:Search]Search service shouldn't be responsible for prompting for engine installation failures
Bug 1664252 R[Toolkit:Places]Stop breaking redirects chains when expiring visits for long urls
Bug 1534986 R[Toolkit:Video/Audio Controls]If a Picture-in-Picture'd video requests fullscreen, Picture-in-Picture should exit first
Bug 1599376 R[Toolkit:Video/Audio Controls]Picture-in-Picture window can not be opened using the keyboard shortcut on macOS
Bug 1599803 R[Toolkit:Video/Audio Controls]Factor out repeated logic in Picture-in-Picture tests
Bug 1603234 R[Toolkit:Video/Audio Controls]Picture-in-Picture close button is on the wrong side on macOS
###########
Changes to 19 bugs - 17 fixed.