Don't pushState when setting the search page to itself.

Calling pushState when the search page is shown causes history entries after
the current one to be lost.

This mimics the pre-r271538 behavior where it set location.hash. Setting
location.hash is a no-op (rather than pushing a duplicate history entry) if the
hash has not changed.

BUG=401004

Review URL: https://codereview.chromium.org/446093002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@287892 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/resources/options/search_page.js

@@ -267,10 +267,12 @@ cr.define('options', function() {
       // Cleanup the search query string.
       text = SearchPage.canonicalizeQuery(text);
 
-      // Set the hash on the current page, and the enclosing uber page
+      // Set the hash on the current page, and the enclosing uber page. Only do
+      // this if the page is not current. See https://crbug.com/401004.
       var hash = text ? '#' + encodeURIComponent(text) : '';
       var path = text ? this.name : '';
-      uber.pushState({}, path + hash);
+      if (location.hash != hash || location.pathname != '/' + path)
+        uber.pushState({}, path + hash);
 
       // Toggle the search page if necessary.
       if (text) {