Skeleton implementation of CSS Properties and Values API

third_party/WebKit/Source/core/css/resolver/CSSVariableResolver.cpp

Index: third_party/WebKit/Source/core/css/resolver/CSSVariableResolver.cpp
diff --git a/third_party/WebKit/Source/core/css/resolver/CSSVariableResolver.cpp b/third_party/WebKit/Source/core/css/resolver/CSSVariableResolver.cpp
index 4a00f6156fe49356acf0347e8e3a529d59c0fc28..cee2426bda3e5a155e78144841cff46de775a2b8 100644
--- a/third_party/WebKit/Source/core/css/resolver/CSSVariableResolver.cpp
+++ b/third_party/WebKit/Source/core/css/resolver/CSSVariableResolver.cpp
@@ -12,10 +12,12 @@
 #include "core/css/CSSUnsetValue.h"
 #include "core/css/CSSVariableData.h"
 #include "core/css/CSSVariableReferenceValue.h"
+#include "core/css/PropertyRegistry.h"
 #include "core/css/parser/CSSParserToken.h"
 #include "core/css/parser/CSSParserTokenRange.h"
 #include "core/css/parser/CSSPropertyParser.h"
 #include "core/css/resolver/StyleBuilder.h"
+#include "core/css/resolver/StyleBuilderConverter.h"
 #include "core/css/resolver/StyleResolverState.h"
 #include "core/style/StyleVariableData.h"
 #include "wtf/Vector.h"
@@ -33,6 +35,8 @@ bool CSSVariableResolver::resolveFallback(CSSParserTokenRange range, Vector<CSSP
 
 CSSVariableData* CSSVariableResolver::valueForCustomProperty(AtomicString name)
 {
+    // TODO(timloh): Registered properties shouldn't return nullptr in failure
+    // cases (aside from cycles?), but instead return the initial/inherited value.
     if (m_variablesSeen.contains(name)) {
         m_cycleStartPoints.add(name);
         return nullptr;
@@ -46,6 +50,25 @@ CSSVariableData* CSSVariableResolver::valueForCustomProperty(AtomicString name)
     if (!variableData->needsVariableResolution())
         return variableData;
     RefPtr<CSSVariableData> newVariableData = resolveCustomProperty(name, *variableData);
+
+    DCHECK(m_registry || !RuntimeEnabledFeatures::cssVariables2Enabled());
+    if (m_registry) {
+        const PropertyRegistry::Registration* registration = m_registry->registration(name);
+        if (registration) {
+            const CSSValue* parsedValue = nullptr;
+            if (newVariableData) {
+                parsedValue = newVariableData->parseForSyntax(registration->syntax());
+                if (parsedValue)
+                    parsedValue = &StyleBuilderConverter::convertRegisteredPropertyValue(m_styleResolverState, *parsedValue);
+                else
+                    newVariableData = nullptr;
+            }
+            m_styleVariableData->setVariable(name, newVariableData);
+            m_styleVariableData->setRegisteredInheritedProperty(name, parsedValue);
+            return newVariableData.get();
+        }
+    }
+
     m_styleVariableData->setVariable(name, newVariableData);
     return newVariableData.get();
 }
@@ -134,7 +157,7 @@ const CSSValue* CSSVariableResolver::resolveVariableReferences(const StyleResolv
 {
     ASSERT(!isShorthandProperty(id));
 
-    CSSVariableResolver resolver(state.style()->variables());
+    CSSVariableResolver resolver(state);
     Vector<CSSParserToken> tokens;
     if (!resolver.resolveTokenRange(value.variableDataValue()->tokens(), tokens))
         return CSSUnsetValue::create();
@@ -155,7 +178,7 @@ const CSSValue* CSSVariableResolver::resolvePendingSubstitutions(StyleResolverSt
         CSSVariableReferenceValue* shorthandValue = pendingValue.shorthandValue();
         CSSPropertyID shorthandPropertyId = pendingValue.shorthandPropertyId();
 
-        CSSVariableResolver resolver(state.style()->variables());
+        CSSVariableResolver resolver(state);
 
         Vector<CSSParserToken> tokens;
         if (resolver.resolveTokenRange(shorthandValue->variableDataValue()->tokens(), tokens)) {
@@ -180,21 +203,24 @@ const CSSValue* CSSVariableResolver::resolvePendingSubstitutions(StyleResolverSt
 }
 
 
-void CSSVariableResolver::resolveVariableDefinitions(StyleVariableData* variables)
+void CSSVariableResolver::resolveVariableDefinitions(const StyleResolverState& state)
 {
+    StyleVariableData* variables = state.style()->variables();
     if (!variables)
         return;
 
-    CSSVariableResolver resolver(variables);
-    for (auto& variable : variables->m_data) {
-        if (variable.value && variable.value->needsVariableResolution())
-            variable.value = resolver.resolveCustomProperty(variable.key, *variable.value);
-    }
+    CSSVariableResolver resolver(state);
+    for (auto& variable : variables->m_data)
+        resolver.valueForCustomProperty(variable.key);

[meade_UTC10, 2016/09/06 04:52:06]

This loop looks like it shouldn't do anything (when compared to the LHS anyway).
Perhaps valueForCustomProperty needs renaming? It seems like it does the
resolving for the property if needed, as well as returning the value.

[Timothy Loh, 2016/09/06 08:21:17]

Agreed, but I don't have any good names here (suggestions welcome)

 }
 
-CSSVariableResolver::CSSVariableResolver(StyleVariableData* styleVariableData)
-    : m_styleVariableData(styleVariableData)
+CSSVariableResolver::CSSVariableResolver(const StyleResolverState& state)
+    : m_styleResolverState(state)
+    , m_styleVariableData(state.style()->variables())
+    , m_registry(state.document().propertyRegistry())
 {
 }
 
+DEFINE_TRACE(CSSVariableResolver) { visitor->trace(m_registry); }
+
 } // namespace blink