The MobileViewportManager ("MVM") is responsible for setting the CSS viewport on
any of the following events:
- a page is painted for the first time (on the before-first-paint event)
- a meta-viewport tag is added (on the DOMMetaAdded event)
- the full-zoom is changed (on the FullZoomChanged event)
- if the window is resized (ResizeReflow gets called as part of normal layout
processing, and this will pick up a new CSS viewport from MVM)
If the CSS viewport changes or if it is the initial paint, the MVM additionally
calls SetResolutionAndScaleTo on the presShell to update the displayed zoom.
The APZ code in AsyncPanZoomController::NotifyLayersUpdated already has
corresponding code to accept this updated zoom when the CSS viewport changes.
The MobileViewportManager ("MVM") is responsible for setting the CSS viewport on
any of the following events:
- a page is painted for the first time (on the before-first-paint event)
- a meta-viewport tag is added (on the DOMMetaAdded event)
- the full-zoom is changed (on the FullZoomChanged event)
- if the window is resized (ResizeReflow gets called as part of normal layout
processing, and this will pick up a new CSS viewport from MVM)
If the CSS viewport changes or if it is the initial paint, the MVM additionally
calls SetResolutionAndScaleTo on the presShell to update the displayed zoom.
The APZ code in AsyncPanZoomController::NotifyLayersUpdated already has
corresponding code to accept this updated zoom when the CSS viewport changes.
