Bug 1171708 - Use localName when detecting <xul:browsers> for XULFrameLoaderCreated. r=billm

We were using tagName before, which is fine for the dynamically created browsers
in new tabs, but not fine for the initial browser tab, which has a tagName of
"xul:browser" instead of "browser". Using localName makes sure that we don't
get the XML namespace included with the node name. We check the XUL namespace
separately be checking the namespaceURI.

--HG--
extra : commitid : 8YXH7ZrS0lc
extra : source : 451741a8b932024db0c5e54184667b6db970813a

browser/components/sessionstore/SessionStore.jsm

@@ -126,6 +126,8 @@ const TAB_EVENTS = [
   "TabUnpinned"
 ];
 
+const NS_XUL = "http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul";
+
 Cu.import("resource://gre/modules/Services.jsm", this);
 Cu.import("resource://gre/modules/XPCOMUtils.jsm", this);
 Cu.import("resource://gre/modules/TelemetryTimestamps.jsm", this);
@@ -877,7 +879,10 @@ var SessionStoreInternal = {
         this.onBrowserCrashed(win, target);
         break;
       case "XULFrameLoaderCreated":
-        if (target.tagName == "browser" && target.frameLoader && target.permanentKey) {
+        if (target.namespaceURI == NS_XUL &&
+            target.localName == "browser" &&
+            target.frameLoader &&
+            target.permanentKey) {
           this._lastKnownFrameLoader.set(target.permanentKey, target.frameLoader);
           this.resetEpoch(target);
         }