Avoid always style recalc when removing stylesheets.

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index 16a79a962d866b6a80236840416016209358832d..b8c6aa1a228392d60fb44f578e66f9cadee65568 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -5326,4 +5326,22 @@ DocumentLifecycleNotifier* Document::lifecycleNotifier()
     return static_cast<DocumentLifecycleNotifier*>(ExecutionContext::lifecycleNotifier());
 }
 
+void Document::removedStyleSheet(StyleSheet* sheet, RecalcStyleTime when, StyleResolverUpdateMode updateMode)
+{
+    if (!isActive())
+        return;
+
+    styleEngine()->modifiedStyleSheet(sheet);
+    styleResolverChanged(when, updateMode);
+}
+
+void Document::modifiedStyleSheet(StyleSheet* sheet, RecalcStyleTime when, StyleResolverUpdateMode updateMode)
+{
+    if (!isActive())
+        return;
+
+    styleEngine()->modifiedStyleSheet(sheet);
+    styleResolverChanged(when, updateMode);
+}
+
 } // namespace WebCore