Bug 1590816 - Make GetLinkDocument a static function again. r=mak

Now without a duplicate version on another file :)

Differential Revision: https://phabricator.services.mozilla.com/D50266

--HG--
extra : moz-landing-system : lando

docshell/base/BaseHistory.cpp

@@ -14,7 +14,7 @@ namespace mozilla {
 using mozilla::dom::Document;
 using mozilla::dom::Link;
 
-Document* BaseHistory::GetLinkDocument(Link& aLink) {
+static Document* GetLinkDocument(const Link& aLink) {
   Element* element = aLink.GetElement();
   // Element can only be null for mock_Link.
   return element ? element->OwnerDoc() : nullptr;

docshell/base/BaseHistory.h

@@ -31,8 +31,6 @@ class BaseHistory : public IHistory {
   // use the results anymore.
   virtual void CancelVisitedQueryIfPossible(nsIURI*) = 0;
 
-  static dom::Document* GetLinkDocument(dom::Link&);
-
   using ObserverArray = nsTObserverArray<dom::Link*>;
   struct TrackedURI {
     ObserverArray mLinks;