Mac: Enable help when there are no windows.

chrome/browser/app_controller_mac.mm

Index: chrome/browser/app_controller_mac.mm
diff --git a/chrome/browser/app_controller_mac.mm b/chrome/browser/app_controller_mac.mm
index edf3615e0c3b09593c019d445ad7ad6653b046fd..434f61e5e399bdfff4a07eda2dfc7be39a98ec61 100644
--- a/chrome/browser/app_controller_mac.mm
+++ b/chrome/browser/app_controller_mac.mm
@@ -502,13 +502,17 @@
       BrowserList::GetLastActive()->
           ExecuteCommandWithDisposition(IDC_OPEN_FILE, CURRENT_TAB);
       break;
-    case IDC_CLEAR_BROWSING_DATA:
+    case IDC_CLEAR_BROWSING_DATA: {
       // There may not be a browser open, so use the default profile.
       scoped_nsobject<ClearBrowsingDataController> controller(
           [[ClearBrowsingDataController alloc]
               initWithProfile:defaultProfile]);
       [controller runModalDialog];
       break;
+    }
+    case IDC_HELP_PAGE:
+      Browser::OpenHelpWindow(defaultProfile);
+      break;
   };
 }
 
@@ -538,6 +542,7 @@
   menuState_->UpdateCommandEnabled(IDC_OPEN_FILE, true);
   menuState_->UpdateCommandEnabled(IDC_CLEAR_BROWSING_DATA, true);
   menuState_->UpdateCommandEnabled(IDC_RESTORE_TAB, false);
+  menuState_->UpdateCommandEnabled(IDC_HELP_PAGE, true);
   // TODO(pinkerton): ...more to come...
 }