Add position keys to backdrop and flexbox (web-platform-dx#2134)

Author: jamesnw

features/backdrop.yml

@@ -2,5 +2,8 @@ name: "::backdrop"
 description: The `::backdrop` CSS pseudo-element is a box underneath an element in the top layer, such as a `<dialog>`. It can be used to create obscuring effects distinguishing a modal element from the elements underneath.
 spec: https://drafts.csswg.org/css-position-4/#backdrop
 group: selectors
+status:
+  compute_from: css.selectors.backdrop
 compat_features:
   - css.selectors.backdrop
+  - css.selectors.backdrop.inherit_from_originating_element

features/backdrop.yml.dist

@@ -14,4 +14,28 @@ status:
     safari: "15.4"
     safari_ios: "15.4"
 compat_features:
+  # ⬇️ Same status as overall feature ⬇️
+  # baseline: high
+  # baseline_low_date: 2022-03-14
+  # baseline_high_date: 2024-09-14
+  # support:
+  #   chrome: "37"
+  #   chrome_android: "37"
+  #   edge: "79"
+  #   firefox: "47"
+  #   firefox_android: "47"
+  #   safari: "15.4"
+  #   safari_ios: "15.4"
   - css.selectors.backdrop
+
+  # baseline: low
+  # baseline_low_date: 2024-03-05
+  # support:
+  #   chrome: "122"
+  #   chrome_android: "122"
+  #   edge: "122"
+  #   firefox: "120"
+  #   firefox_android: "120"
+  #   safari: "17.4"
+  #   safari_ios: "17.4"
+  - css.selectors.backdrop.inherit_from_originating_element

features/flexbox.yml

@@ -3,16 +3,31 @@ description: Flexbox is a one-dimensional layout system, which places content ei
 spec: https://drafts.csswg.org/css-flexbox-1/
 group: flexbox
 caniuse: flexbox
-# Status is manually set to match https://caniuse.com/flexbox.
-# TODO: https://github.com/web-platform-dx/web-features/pull/1227
 status:
-  baseline: high
-  baseline_low_date: 2015-09-30
-  support:
-    chrome: "29"
-    chrome_android: "29"
-    edge: "12"
-    firefox: "28"
-    firefox_android: "28"
-    safari: "9"
-    safari_ios: "9"
+  compute_from: css.properties.display.flex
+compat_features:
+  - css.properties.display.flex
+  - css.properties.display.inline-flex
+  - css.properties.flex
+  - css.properties.flex-direction
+  - css.properties.flex-grow
+  - css.properties.flex-shrink
+  - css.properties.order
+  - css.properties.flex-basis
+  - css.properties.flex-basis.auto
+  - css.properties.align-content.flex_context
+  - css.properties.flex-flow
+  - css.properties.flex-wrap
+  - css.properties.align-self.flex_context
+  - css.properties.align-items.flex_context
+  - css.properties.justify-content.flex_context
+  - css.properties.justify-items.flex_context
+  - css.properties.align-content.flex_context.stretch
+  - css.properties.align-self.flex_context.stretch
+  - css.properties.justify-content.flex_context.stretch
+  - css.properties.place-content.flex_context
+  - css.properties.place-items.flex_context
+  - css.properties.place-self.flex_context
+  - css.properties.align-self.flex_context.baseline
+  - css.properties.align-items.flex_context.baseline
+  - css.properties.position.absolutely_positioned_flex_children

features/flexbox.yml.dist

@@ -1,7 +1,20 @@
 # Generated from: flexbox.yml
 # Do not edit this file by hand. Edit the source file instead!
 
+status:
+  baseline: high
+  baseline_low_date: 2015-09-30
+  baseline_high_date: 2018-03-30
+  support:
+    chrome: "29"
+    chrome_android: "29"
+    edge: "12"
+    firefox: "20"
+    firefox_android: "20"
+    safari: "9"
+    safari_ios: "9"
 compat_features:
+  # ⬇️ Same status as overall feature ⬇️
   # baseline: high
   # baseline_low_date: 2015-09-30
   # baseline_high_date: 2018-03-30
@@ -78,6 +91,19 @@ compat_features:
   - css.properties.justify-content.flex_context
   - css.properties.justify-items.flex_context
 
+  # baseline: high
+  # baseline_low_date: 2017-09-19
+  # baseline_high_date: 2020-03-19
+  # support:
+  #   chrome: "52"
+  #   chrome_android: "52"
+  #   edge: "12"
+  #   firefox: "52"
+  #   firefox_android: "52"
+  #   safari: "11"
+  #   safari_ios: "11"
+  - css.properties.position.absolutely_positioned_flex_children
+
   # baseline: high
   # baseline_low_date: 2020-01-15
   # baseline_high_date: 2022-07-15