Remove global list map of TreeScope to StyleSheetCollection.

sky/engine/core/dom/shadow/ShadowRoot.cpp

Index: sky/engine/core/dom/shadow/ShadowRoot.cpp
diff --git a/sky/engine/core/dom/shadow/ShadowRoot.cpp b/sky/engine/core/dom/shadow/ShadowRoot.cpp
index 04c696c743ba28457f75c762d06d03557e241d8b..0faf6614c561d4a2cd9a734b6fddee1ba233ec1b 100644
--- a/sky/engine/core/dom/shadow/ShadowRoot.cpp
+++ b/sky/engine/core/dom/shadow/ShadowRoot.cpp
@@ -55,9 +55,6 @@ ShadowRoot::ShadowRoot(Document& document)
 
 ShadowRoot::~ShadowRoot()
 {
-    if (StyleEngine* styleEngine = document().styleEngine())
-        styleEngine->didRemoveShadowRoot(this);
-
     // We cannot let ContainerNode destructor call willBeDeletedFromDocument()
     // for this ShadowRoot instance because TreeScope destructor
     // clears Node::m_treeScope thus ContainerNode is no longer able