Bugzilla

The frame state bit NS_STATE_IS_OUTER_SVG is redundant: Setting this bit is exactly equal to being an `nsSVGOuterSVGFrame`, checking the bit can be done by nsIFrame::IsSVGOuterSVGFrame() https://dxr.mozilla.org/mozilla-central/source/layout/generic/nsIFrame.h#2804. There is little (if any) performance difference.

This bit is arguably harmful, because it is a shared bit at 20 conflicting with aother irrelevant bit (NS_BLOCK_NEEDS_BIDI_RESOLUTION) due to lack of bits. Without heeding this, one may write code with hidden bugs.

There isn't many places using this bit, we can easily clean them up.

The frame state bit NS_STATE_IS_OUTER_SVG is redundant: Setting this bit is exactly equal to being an `nsSVGOuterSVGFrame`, checking the bit can be done by nsIFrame::IsSVGOuterSVGFrame() https://dxr.mozilla.org/mozilla-central/source/layout/generic/nsIFrame.h#2804. There is little (if any) performance difference.

This bit is arguably harmful, because it is a shared bit at 20 conflicting with aother irrelevant bit (NS_BLOCK_NEEDS_BIDI_RESOLUTION) due to lack of bits. Without heeding this, one may write code with hidden bugs.

There aren't many places using this bit, we can easily clean them up.

The frame state bit NS_STATE_IS_OUTER_SVG is redundant: Setting this bit is exactly equal to being an `nsSVGOuterSVGFrame`, checking the bit can be done by nsIFrame::IsSVGOuterSVGFrame() https://dxr.mozilla.org/mozilla-central/source/layout/generic/nsIFrame.h#2804. There is little (if any) performance difference.

This bit is arguably harmful, because it is a shared bit at 20 conflicting with aother irrelevant bit (NS_BLOCK_NEEDS_BIDI_RESOLUTION) due to lack of bits. Without heeding this, one may write code with hidden bugs.

There aren't many places using this bit, we can easily clean them up.

Some context: https://bugzilla.mozilla.org/show_bug.cgi?id=1504072#c6