Options: Fix to enable "Use current pages" to make new URLs to open when chrome restarts.

Made changes to enable the button only on below conditions
1) If pref is user editable. In this case event.value['disabled'] would be false.
2) If pref is user editable and it does'nt hold a default value. In this case event.value['controlledBy'] would be recommended.
3) Otherwise if controlledBy is empty or null.

BUG=106592
TEST=None.


Review URL: http://codereview.chromium.org/8883015

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@113975 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/resources/options/browser_options.js

@@ -24,7 +24,7 @@ cr.define('options', function() {
 
     startup_pages_pref_: {
       'name': 'session.urls_to_restore_on_startup',
-      'managed': false
+      'disabled': false
     },
 
     /**
@@ -247,7 +247,7 @@ cr.define('options', function() {
      */
     shouldEnableCustomStartupPageControls: function(pages) {
       return $('startupShowPagesButton').checked &&
-          !this.startup_pages_pref_.controlledBy;
+          !this.startup_pages_pref_.disabled;
     },
 
     /**
@@ -288,7 +288,7 @@ cr.define('options', function() {
      * @private
      */
     handleStartupPageListChange_: function(event) {
-      this.startup_pages_pref_.controlledBy = event.value['controlledBy'];
+      this.startup_pages_pref_.disabled = event.value['disabled'];
       this.updateCustomStartupPageControlStates_();
     },