Rename StyleSheetCollections to StyleEngine.

Source/core/dom/Element.cpp

Index: Source/core/dom/Element.cpp
diff --git a/Source/core/dom/Element.cpp b/Source/core/dom/Element.cpp
index 02518c5bcfad6a3e0e43c5279e4d700cd817c74a..0b2abe9ad87bfb15a9aaa91114e1f25fc0d44396 100644
--- a/Source/core/dom/Element.cpp
+++ b/Source/core/dom/Element.cpp
@@ -1502,7 +1502,7 @@ StyleRecalcChange Element::recalcOwnStyle(StyleRecalcChange change)
 
     // If "rem" units are used anywhere in the document, and if the document element's font size changes, then go ahead and force font updating
     // all the way down the tree. This is simpler than having to maintain a cache of objects (and such font size changes should be rare anyway).
-    if (document().styleSheetCollections()->usesRemUnits() && document().documentElement() == this && oldStyle && newStyle && oldStyle->fontSize() != newStyle->fontSize()) {
+    if (document().styleEngine()->usesRemUnits() && document().documentElement() == this && oldStyle && newStyle && oldStyle->fontSize() != newStyle->fontSize()) {
         // Cached RenderStyles may depend on the re units.
         document().styleResolver()->invalidateMatchedPropertiesCache();
         return Force;