1691097 - Implement missing WebRender functionality causing us to use blob images

Status: NEW

(Core :: Graphics: WebRender, enhancement)

Description

[Nicolas Silva [:nical]]

Looking at where CreateWebRenderCommands returns false in nsDisplayList,cpp (which triggers the blob image fall-back I gathered this (likely incomplete) list:

• SVG geometry
• themed backgrounds
• nsDisplayBackgroundColor
  • HasBackgroundClipText()
• nsDisplayOutline
  • IsThemedOutline()
• nsDisplayBorder
  • Gradient border
  • mBorderImageRepeatH == StyleBorderImageRepeat::Space (etc.)
  • More stuff (I got lost in layers of indirection).
• nsDisplayBoxShadowOuter
  • nativeTheme
  • if mBoxShadow is emppty (the equivalent painting code early-returns so I think we should not need a blop here)
• nsDisplayBoxShadowInner
  • nativeTheme
• nsDisplayPerspective
  • !GetChildren()->GetTop() (sounds like it should be an early-return?)
• nsDisplayText
  • font size > kWebRenderFontSizeLimit
• nsDisplayBackdropFilters
  • if the filter chain is compatible with webrender
• nsDisplayFilters
  • if the filter chain is compatible with webrender
• nsDisplayBackgroundImage
  • text clip
  • mBackgroundStyle->StyleBackground() is null
  • themed
  • "We only support painting gradients and image for a single style image layer, and we don't support crop-rects."
  • Some more stuff that is hard to understand at a glance in nsCSSRendering::CanBuildWebRenderDisplayItemsForStyleImageLayer
• nsDisplayBackgroundColor
  • text clip
• nsDisplayOutline
  • themed