Fix more warnings on linux

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 8518bf998c9e67807636a52dd56604938a5e5e73..c576a465b4e2f011673a97f90a7280af40393d79 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -1627,12 +1627,10 @@ void Document::inheritHtmlAndBodyElementStyles(StyleRecalcChange change)
     }
 
     WritingMode rootWritingMode = documentElementStyle->writingMode();
-    bool isHorizontalWritingMode = documentElementStyle->isHorizontalWritingMode();
     TextDirection rootDirection = documentElementStyle->direction();
 
     if (!writingModeSetOnDocumentElement() && body()) {
         rootWritingMode = bodyStyle->writingMode();
-        isHorizontalWritingMode = bodyStyle->isHorizontalWritingMode();
     }
 
     if (!directionSetOnDocumentElement() && body())