Bug 1798986 - Track UnstrippedURI in SessionHistory, r=smaug,timhuang

Previously, we tracked UnstrippedURI on the nsDocShellLoadState and LoadInfo,
and manually filled it in to match the previous load when doing a
LOAD_CMD_RELOAD in nsDocShell. It is more consistent with other load types to
instead store the information in the load state, allowing it to be handled
consistently for reloads and other history operations.

Unfortunately, this patch has some extra complexity right now, as it needs to
support both SHIP and non-SHIP session history. This should disappear in the
future when we switch to using exclusively SHIP.

Differential Revision: https://phabricator.services.mozilla.com/D161196

docshell/base/nsDocShellLoadState.h

@@ -249,6 +249,8 @@ class nsDocShellLoadState final {
 
   nsIURI* GetUnstrippedURI() const;
 
+  void SetUnstrippedURI(nsIURI* aUnstrippedURI);
+
   // Give the type of DocShell we're loading into (chrome/content/etc) and
   // origin attributes for the URI we're loading, figure out if we should
   // inherit our principal from the document the load was requested from, or
@@ -329,8 +331,7 @@ class nsDocShellLoadState final {
   void SetLoadIsFromSessionHistory(int32_t aOffset, bool aLoadingCurrentEntry);
   void ClearLoadIsFromSessionHistory();
 
-  void MaybeStripTrackerQueryStrings(mozilla::dom::BrowsingContext* aContext,
-                                     nsIURI* aCurrentUnstrippedURI = nullptr);
+  void MaybeStripTrackerQueryStrings(mozilla::dom::BrowsingContext* aContext);
 
  protected:
   // Destructor can't be defaulted or inlined, as header doesn't have all type