Issue #1641 - Implement CSS flow-root keyword

This is just a clean port of 1322191 and follow-up 1325970. It really seems to add create a new way to access existing code relating to block formatting and floating elements rather than implementing new functionality, and it is mercifully straightforwards.

6 files changed, 15 insertions, 2 deletions

diff --git a/layout/style/nsCSSKeywordList.h b/layout/style/nsCSSKeywordList.h
index 34a46ffce..9045da9ff 100644
--- a/layout/style/nsCSSKeywordList.h
+++ b/layout/style/nsCSSKeywordList.h
@@ -285,6 +285,7 @@ CSS_KEY(flex, flex)
 CSS_KEY(flex-end, flex_end)
 CSS_KEY(flex-start, flex_start)
 CSS_KEY(flip, flip)
+CSS_KEY(flow-root, flow_root)
 CSS_KEY(forwards, forwards)
 CSS_KEY(fraktur, fraktur)
 CSS_KEY(from-image, from_image)
diff --git a/layout/style/nsCSSProps.cpp b/layout/style/nsCSSProps.cpp
index ac2978c27..24c97cf33 100644
--- a/layout/style/nsCSSProps.cpp
+++ b/layout/style/nsCSSProps.cpp
@@ -1345,6 +1345,9 @@ KTableEntry nsCSSProps::kDisplayKTable[] = {
   // The next entry is controlled by the layout.css.display-contents.enabled
   // pref.
   { eCSSKeyword_contents,            StyleDisplay::Contents },
+  // The next entry is controlled by the layout.css.display-flow-root.enabled 
+  // pref.
+  { eCSSKeyword_flow_root,           StyleDisplay::FlowRoot },
   { eCSSKeyword_UNKNOWN,             -1 }
 };
 
diff --git a/layout/style/nsRuleNode.cpp b/layout/style/nsRuleNode.cpp
index 1a451a2ef..036d97f86 100644
--- a/layout/style/nsRuleNode.cpp
+++ b/layout/style/nsRuleNode.cpp
@@ -250,6 +250,7 @@ nsRuleNode::EnsureBlockDisplay(StyleDisplay& display,
   case StyleDisplay::Flex:
   case StyleDisplay::WebkitBox:
   case StyleDisplay::Grid:
+  case StyleDisplay::FlowRoot:
     // do not muck with these at all - already blocks
     // This is equivalent to nsStyleDisplay::IsBlockOutside.  (XXX Maybe we
     // should just call that?)
@@ -293,6 +294,7 @@ nsRuleNode::EnsureInlineDisplay(StyleDisplay& display)
   // see if the display value is already inline
   switch (display) {
     case StyleDisplay::Block:
+    case StyleDisplay::FlowRoot:
       display = StyleDisplay::InlineBlock;
       break;
     case StyleDisplay::Table:
diff --git a/layout/style/nsStyleConsts.h b/layout/style/nsStyleConsts.h
index 6d207aec9..f54387aa8 100644
--- a/layout/style/nsStyleConsts.h
+++ b/layout/style/nsStyleConsts.h
@@ -524,6 +524,7 @@ enum class FillMode : uint32_t;
 enum class StyleDisplay : uint8_t {
   None = 0,
   Block,
+  FlowRoot,
   Inline,
   InlineBlock,
   ListItem,
diff --git a/layout/style/nsStyleStruct.h b/layout/style/nsStyleStruct.h
index 4bda817dd..f49cdc43e 100644
--- a/layout/style/nsStyleStruct.h
+++ b/layout/style/nsStyleStruct.h
@@ -2890,7 +2890,8 @@ struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleDisplay
     return mozilla::StyleDisplay::Block == mDisplay ||
            mozilla::StyleDisplay::ListItem == mDisplay ||
            mozilla::StyleDisplay::InlineBlock == mDisplay ||
-           mozilla::StyleDisplay::TableCaption == mDisplay;
+           mozilla::StyleDisplay::TableCaption == mDisplay ||
+           mozilla::StyleDisplay::FlowRoot == mDisplay;
     // Should TABLE_CELL be included here?  They have
     // block frames nested inside of them.
     // (But please audit all callers before changing.)
@@ -2902,7 +2903,8 @@ struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsStyleDisplay
            mozilla::StyleDisplay::WebkitBox == mDisplay ||
            mozilla::StyleDisplay::Grid == mDisplay ||
            mozilla::StyleDisplay::ListItem == mDisplay ||
-           mozilla::StyleDisplay::Table == mDisplay;
+           mozilla::StyleDisplay::Table == mDisplay ||
+           mozilla::StyleDisplay::FlowRoot == mDisplay;
   }
 
   static bool IsDisplayTypeInlineOutside(mozilla::StyleDisplay aDisplay) {
diff --git a/layout/style/test/property_database.js b/layout/style/test/property_database.js
index c75f7b498..2d6352148 100644
--- a/layout/style/test/property_database.js
+++ b/layout/style/test/property_database.js
@@ -7892,6 +7892,10 @@ if (IsCSSPropertyPrefEnabled("layout.css.background-clip-text.enabled")) {
   );
 }
 
+if (IsCSSPropertyPrefEnabled("layout.css.display-flow-root.enabled")) {
+  gCSSProperties["display"].other_values.push("flow-root");
+}
+
 // Copy aliased properties' fields from their alias targets.
 for (var prop in gCSSProperties) {
   var entry = gCSSProperties[prop];