Added --custom-launcher-page. Adds a page to the experimental launcher.

athena/home/app_list_view_delegate.cc

Index: athena/home/app_list_view_delegate.cc
diff --git a/athena/home/app_list_view_delegate.cc b/athena/home/app_list_view_delegate.cc
index 2bd79aea38fdb28c82c30ff57a356ef1678d5e62..2938bf70af9ba344c6228fd2eb806092e3f8822b 100644
--- a/athena/home/app_list_view_delegate.cc
+++ b/athena/home/app_list_view_delegate.cc
@@ -155,6 +155,11 @@ views::View* AppListViewDelegate::CreateStartPageWebView(
   return NULL;
 }
 
+views::View* AppListViewDelegate::CreateCustomPageWebView(
+    const gfx::Size& size) {
+  return NULL;
+}
+
 bool AppListViewDelegate::IsSpeechRecognitionEnabled() {
   return false;
 }