Theme Installer: Fixes for browsers without pushState.

props gcorne.
see #27055.


git-svn-id: https://develop.svn.wordpress.org/trunk@28141 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/js/theme.js

@@ -1175,6 +1175,12 @@ themes.Router = Backbone.Router.extend({
 
 	themes: function() {
 		$( '.theme-search' ).val( '' );
+	},
+
+	navigate: function() {
+		if ( Backbone.history._hasPushState ) {
+			Backbone.Router.navigate.apply( this, arguments );
+		}
 	}
 
 });
@@ -1572,6 +1578,12 @@ themes.InstallerRouter = Backbone.Router.extend({
 
 	search: function( query ) {
 		$( '.theme-search' ).val( query );
+	},
+
+	navigate: function() {
+		if ( Backbone.history._hasPushState ) {
+			Backbone.Router.navigate.apply( this, arguments );
+		}
 	}
 });