[WIP] Migrate Fullscreen to use top layer instead of RenderFullScreen

Source/core/html/HTMLDialogElement.cpp

Index: Source/core/html/HTMLDialogElement.cpp
diff --git a/Source/core/html/HTMLDialogElement.cpp b/Source/core/html/HTMLDialogElement.cpp
index 42a503d30dcea95d4081a5174ac472d31f69eeed..d77ceb666f0bc692988e0eda70ddde53bd6c838f 100644
--- a/Source/core/html/HTMLDialogElement.cpp
+++ b/Source/core/html/HTMLDialogElement.cpp
@@ -95,6 +95,7 @@ HTMLDialogElement::HTMLDialogElement(Document& document)
     , m_centeringMode(Uninitialized)
     , m_centeredPosition(0)
     , m_returnValue("")
+    , m_modal(false)
 {
     ScriptWrappable::init(this);
 }
@@ -113,6 +114,12 @@ void HTMLDialogElement::close(const String& returnValue, ExceptionState& excepti
     closeDialog(returnValue);
 }
 
+void HTMLDialogElement::removedFrom(ContainerNode* insertionPoint)
+{
+    document().removeFromModalDialogStack(this);
+    HTMLElement::removedFrom(insertionPoint);
+}
+
 void HTMLDialogElement::closeDialog(const String& returnValue)
 {
     if (!fastHasAttribute(openAttr))
@@ -120,7 +127,7 @@ void HTMLDialogElement::closeDialog(const String& returnValue)
     setBooleanAttribute(openAttr, false);
 
     HTMLDialogElement* activeModalDialog = document().activeModalDialog();
-    document().removeFromTopLayer(this);
+    document().removeFromModalDialogStack(this);
     if (activeModalDialog == this)
         inertSubtreesChanged(document());
 
@@ -157,7 +164,7 @@ void HTMLDialogElement::showModal(ExceptionState& exceptionState)
         return;
     }
 
-    document().addToTopLayer(this);
+    document().addToModalDialogStack(this);
     setBooleanAttribute(openAttr, true);
 
     // Throw away the AX cache first, so the subsequent steps don't have a chance of queuing up