Changes in 20201130093031

Built from b0865ea584621ce9e7f68833565e3d8ae117ce32

..index..
Bug 1679693 N[Core:Canvas: WebGL]Update WebGL 2 to allow drawArraysInstanced with no non-instanced active attribs
Bug 1662516 N[Core:Canvas: WebGL]Enable all m-gli jobs on Central
Bug 1677857 R[Core:Fuzzing]Implement fuzzPriv.MP() in FuzzingFunctions
Bug 1679652 R[Core:Graphics]Restored session windows all white, no chrome or content, unusable
Bug 1676559 R[Core:Graphics: WebRender]Improve render task graph
Bug 1678175 R[Core:Internationalization]drudgereport.com shows SimSun font instead of Courier New (default monospace font)
Bug 1679682 R[Core:Layout: Form Controls]Firefox Crashes When the File Input `Browse...` Button Is Hidden and There's an Overflow
Bug 1507347 R[Core:Panning and Zooming]Handle FrameMetrics::mCumulativeResolution being 0 gracefully
Bug 1679208 A[Core:Widget]Improve non-native theme with fractional scaling.
Bug 1645528 A[Core:Widget: Gtk][wayland] Connect nsRefreshDrivers in content processes with a widget-local vsync source
Bug 1678969 R[WebExtensions:Request Handling]Replace MOZ_MUST_USE with [[nodiscard]] in StreamFilterParent
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Changes to 11 bugs - 7 fixed.