Bug 1447358: Unifdef the old style system code. r=jwatt

Summary:
This has been automatically generated using:

  http://dotat.at/prog/unifdef/

And:

find $OBJDIR -type f -name '*.h' |
while read FILE; do
  echo "$FILE"
  unifdef -m -DMOZ_STYLO -UMOZ_OLD_STYLE "$FILE";
done

find $OBJDIR -type f -name '*.cpp' |
while read FILE; do
  echo "$FILE"
  unifdef -m -DMOZ_STYLO -UMOZ_OLD_STYLE "$FILE";
done

MozReview-Commit-ID: I4NdKqbMXzJ

Reviewers: jwatt

Bug #: 1447358

Differential Revision: https://phabricator.services.mozilla.com/D779

dom/html/HTMLBodyElement.cpp

@@ -19,9 +19,6 @@
 #include "nsHTMLStyleSheet.h"
 #include "nsMappedAttributes.h"
 #include "nsIDocShell.h"
-#ifdef MOZ_OLD_STYLE
-#include "nsRuleWalker.h"
-#endif
 #include "nsGlobalWindow.h"
 
 NS_IMPL_NS_NEW_HTML_ELEMENT(Body)