Remove ShadowDOMV1 runtime flag (status=stable)

third_party/WebKit/Source/core/dom/Element.idl

Index: third_party/WebKit/Source/core/dom/Element.idl
diff --git a/third_party/WebKit/Source/core/dom/Element.idl b/third_party/WebKit/Source/core/dom/Element.idl
index a78ad2ed0439f0493d0faddaa2c62e62f8d56227..50dffba1ac0a72ef153e5ef2dd63cf2cefac0ffd 100644
--- a/third_party/WebKit/Source/core/dom/Element.idl
+++ b/third_party/WebKit/Source/core/dom/Element.idl
@@ -81,11 +81,11 @@ interface Element : Node {
     // Shadow DOM
     // http://w3c.github.io/webcomponents/spec/shadow/#extensions-to-element-interface
     [RaisesException, CallWith=ScriptState, MeasureAs=ElementCreateShadowRoot] ShadowRoot createShadowRoot();
-    [RuntimeEnabled=ShadowDOMV1, RaisesException, CallWith=ScriptState, MeasureAs=ElementAttachShadow] ShadowRoot attachShadow(ShadowRootInit shadowRootInitDict);
+    [RaisesException, CallWith=ScriptState, MeasureAs=ElementAttachShadow] ShadowRoot attachShadow(ShadowRootInit shadowRootInitDict);
     NodeList getDestinationInsertionPoints();
     [PerWorldBindings, ImplementedAs=openShadowRoot] readonly attribute ShadowRoot? shadowRoot;
-    [RuntimeEnabled=ShadowDOMV1, Unscopable, CEReactions, Reflect] attribute DOMString slot;
-    [RuntimeEnabled=ShadowDOMV1, ImplementedAs=assignedSlotForBinding] readonly attribute HTMLSlotElement assignedSlot;
+    [Unscopable, CEReactions, Reflect] attribute DOMString slot;
+    [ImplementedAs=assignedSlotForBinding] readonly attribute HTMLSlotElement assignedSlot;
 
     // Pointer Lock
     // https://dvcs.w3.org/hg/pointerlock/raw-file/default/index.html#extensions-to-the-element-interface