Bug 1422931 - Part 2: Make webcomponents preference per-doc. r=smaug

This is to fix the case where preference is restore to false when a testcase
ends, but nsDocument::DeleteShell is called afterwards. So, we make the
preference per-doc and set it when the document is created. The value does not
change for the lifetime of the document.

dom/base/ChildIterator.cpp

@@ -12,6 +12,7 @@
 #include "nsIAnonymousContentCreator.h"
 #include "nsIFrame.h"
 #include "nsCSSAnonBoxes.h"
+#include "nsDocument.h"
 
 namespace mozilla {
 namespace dom {
@@ -66,7 +67,7 @@ ExplicitChildIterator::ExplicitChildIterator(const nsIContent* aParent,
     mIsFirst(aStartAtBeginning),
     mIndexInInserted(0)
 {
-  mParentAsSlot = nsContentUtils::IsWebComponentsEnabled() ?
+  mParentAsSlot = nsDocument::IsWebComponentsEnabled(mParent) ?
     HTMLSlotElement::FromContent(mParent) : nullptr;
 }
 

dom/base/nsContentUtils.cpp

@@ -7534,7 +7534,7 @@ nsContentUtils::IsContentInsertionPoint(nsIContent* aContent)
 bool
 nsContentUtils::HasDistributedChildren(nsIContent* aContent)
 {
-  if (!IsWebComponentsEnabled() || !aContent) {
+  if (!aContent || !nsDocument::IsWebComponentsEnabled(aContent)) {
     return false;
   }
 

dom/base/nsDocument.cpp

@@ -1581,6 +1581,10 @@ nsIDocument::nsIDocument()
   for (auto& cnt : mIncCounters) {
     cnt = 0;
   }
+
+  // Set this when document is created and value stays the same for the lifetime
+  // of the document.
+  mIsWebComponentsEnabled = nsContentUtils::IsWebComponentsEnabled();
 }
 
 nsDocument::nsDocument(const char* aContentType)
@@ -2720,6 +2724,30 @@ nsDocument::IsSynthesized() {
   return synthesized;
 }
 
+bool
+nsDocument::IsWebComponentsEnabled(JSContext* aCx, JSObject* aObject)
+{
+  JS::Rooted<JSObject*> obj(aCx, aObject);
+
+  JSAutoCompartment ac(aCx, obj);
+  JS::Rooted<JSObject*> global(aCx, JS_GetGlobalForObject(aCx, obj));
+  nsCOMPtr<nsPIDOMWindowInner> window =
+    do_QueryInterface(nsJSUtils::GetStaticScriptGlobal(global));
+
+  nsIDocument* doc = window ? window->GetExtantDoc() : nullptr;
+  if (!doc) {
+    return false;
+  }
+
+  return doc->IsWebComponentsEnabled();
+}
+
+bool
+nsDocument::IsWebComponentsEnabled(const nsINode* aNode)
+{
+  return aNode->OwnerDoc()->IsWebComponentsEnabled();
+}
+
 nsresult
 nsDocument::StartDocumentLoad(const char* aCommand, nsIChannel* aChannel,
                               nsILoadGroup* aLoadGroup,

dom/base/nsDocument.h

@@ -665,6 +665,11 @@ public:
   virtual void ResolveScheduledSVGPresAttrs() override;
   bool IsSynthesized();
 
+  // Check whether web components are enabled for the global of aObject.
+  static bool IsWebComponentsEnabled(JSContext* aCx, JSObject* aObject);
+  // Check whether web components are enabled for the document this node belongs
+  // to.
+  static bool IsWebComponentsEnabled(const nsINode* aNode);
 private:
   void AddOnDemandBuiltInUASheet(mozilla::StyleSheet* aSheet);
   void SendToConsole(nsCOMArray<nsISecurityConsoleMessage>& aMessages);

dom/base/nsIDocument.h

@@ -3256,6 +3256,11 @@ public:
   virtual bool AllowPaymentRequest() const = 0;
   virtual void SetAllowPaymentRequest(bool aAllowPaymentRequest) = 0;
 
+  bool IsWebComponentsEnabled() const
+  {
+    return mIsWebComponentsEnabled;
+  }
+
 protected:
   bool GetUseCounter(mozilla::UseCounter aUseCounter)
   {
@@ -3612,6 +3617,9 @@ protected:
   // True if the encoding menu should be disabled.
   bool mEncodingMenuDisabled : 1;
 
+  // True if dom.webcomponents.enabled pref is set when document is created.
+  bool mIsWebComponentsEnabled : 1;
+
   // Whether <style scoped> support is enabled in this document.
   enum { eScopedStyle_Unknown, eScopedStyle_Disabled, eScopedStyle_Enabled };
   unsigned int mIsScopedStyleEnabled : 2;

dom/base/nsTextNode.cpp

@@ -21,6 +21,7 @@
 #ifdef DEBUG
 #include "nsRange.h"
 #endif
+#include "nsDocument.h"
 
 using namespace mozilla;
 using namespace mozilla::dom;
@@ -157,6 +158,12 @@ void nsTextNode::UnbindFromTree(bool aDeep, bool aNullParent)
   nsGenericDOMDataNode::UnbindFromTree(aDeep, aNullParent);
 }
 
+bool
+nsTextNode::IsWebComponentsEnabled(JSContext* aCx, JSObject* aObject)
+{
+  return nsDocument::IsWebComponentsEnabled(aCx, aObject);
+}
+
 #ifdef DEBUG
 void
 nsTextNode::List(FILE* out, int32_t aIndent) const

dom/base/nsTextNode.h

@@ -75,6 +75,10 @@ public:
 
   virtual nsIDOMNode* AsDOMNode() override { return this; }
 
+  // Need to have a copy here because including nsDocument.h in this file will
+  // fail to build on Windows.
+  static bool IsWebComponentsEnabled(JSContext* aCx, JSObject* aObject);
+
 #ifdef DEBUG
   virtual void List(FILE* out, int32_t aIndent) const override;
   virtual void DumpContent(FILE* out, int32_t aIndent, bool aDumpAll) const override;

dom/html/HTMLSlotElement.cpp

@@ -16,7 +16,7 @@ NS_NewHTMLSlotElement(already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo,
                       mozilla::dom::FromParser aFromParser)
 {
   RefPtr<mozilla::dom::NodeInfo> nodeInfo(aNodeInfo);
-  if (nsContentUtils::IsWebComponentsEnabled()) {
+  if (nsDocument::IsWebComponentsEnabled(nodeInfo->GetDocument())) {
     already_AddRefed<mozilla::dom::NodeInfo> nodeInfoArg(nodeInfo.forget());
     return new mozilla::dom::HTMLSlotElement(nodeInfoArg);
   }

dom/webidl/Element.webidl

@@ -254,19 +254,19 @@ dictionary ShadowRootInit {
 // https://dom.spec.whatwg.org/#element
 partial interface Element {
   // Shadow DOM v1
-  [Throws, Pref="dom.webcomponents.enabled"]
+  [Throws, Func="nsDocument::IsWebComponentsEnabled"]
   ShadowRoot attachShadow(ShadowRootInit shadowRootInitDict);
-  [BinaryName="shadowRootByMode", Pref="dom.webcomponents.enabled"]
+  [BinaryName="shadowRootByMode", Func="nsDocument::IsWebComponentsEnabled"]
   readonly attribute ShadowRoot? shadowRoot;
-  [BinaryName="assignedSlotByMode", Pref="dom.webcomponents.enabled"]
+  [BinaryName="assignedSlotByMode", Func="nsDocument::IsWebComponentsEnabled"]
   readonly attribute HTMLSlotElement? assignedSlot;
-  [CEReactions, Unscopable, SetterThrows, Pref="dom.webcomponents.enabled"]
+  [CEReactions, Unscopable, SetterThrows, Func="nsDocument::IsWebComponentsEnabled"]
            attribute DOMString slot;
 
   // [deprecated] Shadow DOM v0
-  [Throws, Pref="dom.webcomponents.enabled"]
+  [Throws, Func="nsDocument::IsWebComponentsEnabled"]
   ShadowRoot createShadowRoot();
-  [Pref="dom.webcomponents.enabled"]
+  [Func="nsDocument::IsWebComponentsEnabled"]
   NodeList getDestinationInsertionPoints();
 };
 

dom/webidl/HTMLSlotElement.webidl

@@ -11,7 +11,7 @@
  * and create derivative works of this document.
  */
 
-[Pref="dom.webcomponents.enabled", Exposed=Window, HTMLConstructor]
+[Func="nsDocument::IsWebComponentsEnabled", Exposed=Window, HTMLConstructor]
 interface HTMLSlotElement : HTMLElement {
   [CEReactions, SetterThrows] attribute DOMString name;
   sequence<Node> assignedNodes(optional AssignedNodesOptions options);

dom/webidl/ShadowRoot.webidl

@@ -17,7 +17,7 @@ enum ShadowRootMode {
 };
 
 // https://dom.spec.whatwg.org/#shadowroot
-[Pref="dom.webcomponents.enabled"]
+[Func="nsDocument::IsWebComponentsEnabled"]
 interface ShadowRoot : DocumentFragment
 {
   // Shadow DOM v1

dom/webidl/Text.webidl

@@ -19,7 +19,7 @@ interface Text : CharacterData {
 };
 
 partial interface Text {
-  [BinaryName="assignedSlotByMode", Pref="dom.webcomponents.enabled"]
+  [BinaryName="assignedSlotByMode", Func="nsTextNode::IsWebComponentsEnabled"]
   readonly attribute HTMLSlotElement? assignedSlot;
 };