Bug 1378079 - Part 2: Introduce throw-on-dynamic-markup-insertion counter.

Per spec, document objects have a throw-on-dynamic-markup-insertion counter, which is used in conjunction with the create an element for the token algorithm to prevent custom element constructors from being able to use document.open(), document.close(), and document.write() when they are invoked by the parser.

Tag UXP Issue #1344

dom/base/nsDocument.cpp

@@ -1329,7 +1329,8 @@ nsIDocument::nsIDocument()
     mFrameRequestCallbacksScheduled(false),
     mBidiOptions(IBMBIDI_DEFAULT_BIDI_OPTIONS),
     mPartID(0),
-    mUserHasInteracted(false)
+    mUserHasInteracted(false),
+    mThrowOnDynamicMarkupInsertionCounter(0)
 {
   SetIsInDocument();
 

dom/base/nsIDocument.h

@@ -2879,6 +2879,22 @@ public:
   virtual void ScheduleIntersectionObserverNotification() = 0;
   virtual void NotifyIntersectionObservers() = 0;
 
+  bool ShouldThrowOnDynamicMarkupInsertion()
+  {
+    return mThrowOnDynamicMarkupInsertionCounter;
+  }
+
+  void IncrementThrowOnDynamicMarkupInsertionCounter()
+  {
+    ++mThrowOnDynamicMarkupInsertionCounter;
+  }
+
+  void DecrementThrowOnDynamicMarkupInsertionCounter()
+  {
+    MOZ_ASSERT(mThrowOnDynamicMarkupInsertionCounter);
+    --mThrowOnDynamicMarkupInsertionCounter;
+  }
+
 protected:
   bool GetUseCounter(mozilla::UseCounter aUseCounter)
   {
@@ -3326,6 +3342,11 @@ protected:
 
   uint32_t mBlockDOMContentLoaded;
 
+  // Used in conjunction with the create-an-element-for-the-token algorithm to
+  // prevent custom element constructors from being able to use document.open(),
+  // document.close(), and document.write() when they are invoked by the parser.
+  uint32_t mThrowOnDynamicMarkupInsertionCounter;
+
   // Our live MediaQueryLists
   PRCList mDOMMediaQueryLists;
 
@@ -3399,6 +3420,23 @@ private:
   uint32_t                mMicroTaskLevel;
 };
 
+class MOZ_RAII AutoSetThrowOnDynamicMarkupInsertionCounter final {
+  public:
+    explicit AutoSetThrowOnDynamicMarkupInsertionCounter(
+      nsIDocument* aDocument)
+      : mDocument(aDocument)
+    {
+      mDocument->IncrementThrowOnDynamicMarkupInsertionCounter();
+    }
+
+    ~AutoSetThrowOnDynamicMarkupInsertionCounter() {
+      mDocument->DecrementThrowOnDynamicMarkupInsertionCounter();
+    }
+
+  private:
+    nsIDocument* mDocument;
+};
+
 // XXX These belong somewhere else
 nsresult
 NS_NewHTMLDocument(nsIDocument** aInstancePtrResult, bool aLoadedAsData = false);

dom/html/nsHTMLDocument.cpp

@@ -1401,6 +1401,11 @@ nsHTMLDocument::Open(JSContext* cx,
     return nullptr;
   }
 
+  if (ShouldThrowOnDynamicMarkupInsertion()) {
+    aError.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return nullptr;
+  }
+
   // Set up the content type for insertion
   nsAutoCString contentType;
   contentType.AssignLiteral("text/html");
@@ -1608,6 +1613,11 @@ nsHTMLDocument::Close(ErrorResult& rv)
     return;
   }
 
+  if (ShouldThrowOnDynamicMarkupInsertion()) {
+    rv.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
+    return;
+  }
+
   if (!mParser || !mParser->IsScriptCreated()) {
     return;
   }
@@ -1683,6 +1693,10 @@ nsHTMLDocument::WriteCommon(JSContext *cx,
     return NS_ERROR_DOM_INVALID_STATE_ERR;
   }
 
+  if (ShouldThrowOnDynamicMarkupInsertion()) {
+    return NS_ERROR_DOM_INVALID_STATE_ERR;
+  }
+
   if (mParserAborted) {
     // Hixie says aborting the parser doesn't undefine the insertion point.
     // However, since we null out mParser in that case, we track the