Implement CSS parser part for ::slotted pseudo element

third_party/WebKit/Source/core/css/CSSSelector.cpp

Index: third_party/WebKit/Source/core/css/CSSSelector.cpp
diff --git a/third_party/WebKit/Source/core/css/CSSSelector.cpp b/third_party/WebKit/Source/core/css/CSSSelector.cpp
index 2910c45972c2fd945cbc0bc497337606b813006f..ef91085506abb8f11b546bcdedb7ea38466c5bc3 100644
--- a/third_party/WebKit/Source/core/css/CSSSelector.cpp
+++ b/third_party/WebKit/Source/core/css/CSSSelector.cpp
@@ -264,6 +264,7 @@ PseudoId CSSSelector::pseudoId(PseudoType type)
     case PseudoFullScreenAncestor:
     case PseudoSpatialNavigationFocus:
     case PseudoListBox:
+    case PseudoSlotted:
         return NOPSEUDO;
     }
 
@@ -367,6 +368,7 @@ const static NameToPseudoStruct pseudoTypeWithArgumentsMap[] = {
 {"nth-last-child",   CSSSelector::PseudoNthLastChild},
 {"nth-last-of-type", CSSSelector::PseudoNthLastOfType},
 {"nth-of-type",      CSSSelector::PseudoNthOfType},
+{"slotted",          CSSSelector::PseudoSlotted},
 };
 
 class NameToPseudoCompare {
@@ -481,6 +483,7 @@ void CSSSelector::updatePseudoType(const AtomicString& value, bool hasArguments)
     case PseudoWebKitCustomElement:
     case PseudoContent:
     case PseudoShadow:
+    case PseudoSlotted:

[rune, 2016/01/13 09:59:09]

The selectors are web-facing in the sense that ::slotted(*) {} rules are not
dropped from the CSSOM unless you do a runtime flag check for shadow dom V1
somewhere.

[kochi, 2016/01/14 09:02:20]

Done in CSSSelectorParser.cpp.

         if (m_match != PseudoElement)
             m_pseudoType = PseudoUnknown;
         break;
@@ -729,6 +732,7 @@ String CSSSelector::selectorText(const String& rightSide) const
         case SubSelector:
             ASSERT_NOT_REACHED();
         case ShadowPseudo:
+        case ShadowSlot:
             return tagHistory->selectorText(str.toString() + rightSide);
         }
     }
@@ -799,6 +803,7 @@ static bool validateSubSelector(const CSSSelector* selector)
     case CSSSelector::PseudoNot:
     case CSSSelector::PseudoSpatialNavigationFocus:
     case CSSSelector::PseudoListBox:
+    case CSSSelector::PseudoSlotted:
         return true;
     default:
         return false;