Introduce :-internal-shadow-host-has-appearance pseudo class, and apply it to METER 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 4355b9d8c4e79ab47d22a56db40a8d4d283454a0..30aca11563a8d54966f720caa1716940f155d9aa 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 PseudoHostHasAppearance:
     case PseudoSlotted:
         return PseudoIdNone;
     }
@@ -290,6 +291,7 @@ const static NameToPseudoStruct pseudoTypeWithoutArgumentsMap[] = {
 {"-internal-media-controls-text-track-list-item-input", CSSSelector::PseudoWebKitCustomElement},
 {"-internal-media-controls-text-track-list-kind-captions", CSSSelector::PseudoWebKitCustomElement},
 {"-internal-media-controls-text-track-list-kind-subtitles", CSSSelector::PseudoWebKitCustomElement},
+{"-internal-shadow-host-has-appearance", CSSSelector::PseudoHostHasAppearance},
 {"-internal-spatial-navigation-focus", CSSSelector::PseudoSpatialNavigationFocus},
 {"-webkit-any-link",              CSSSelector::PseudoAnyLink},
 {"-webkit-autofill",              CSSSelector::PseudoAutofill},
@@ -522,6 +524,7 @@ void CSSSelector::updatePseudoType(const AtomicString& value, bool hasArguments)
     case PseudoHorizontal:
     case PseudoHost:
     case PseudoHostContext:
+    case PseudoHostHasAppearance:
     case PseudoHover:
     case PseudoInRange:
     case PseudoIncrement:
@@ -804,6 +807,7 @@ static bool validateSubSelector(const CSSSelector* selector)
     case CSSSelector::PseudoNot:
     case CSSSelector::PseudoSpatialNavigationFocus:
     case CSSSelector::PseudoListBox:
+    case CSSSelector::PseudoHostHasAppearance:
         return true;
     default:
         return false;