add divider between tabs and regular buttons in room header

res/css/_components.scss

@@ -7,6 +7,7 @@
 @import "./structures/_CustomRoomTagPanel.scss";
 @import "./structures/_FilePanel.scss";
 @import "./structures/_GroupView.scss";
+@import "./structures/_HeaderButtons.scss";
 @import "./structures/_HomePage.scss";
 @import "./structures/_LeftPanel.scss";
 @import "./structures/_MatrixChat.scss";

res/css/structures/_HeaderButtons.scss

@@ -0,0 +1,28 @@
+/*
+Copyright 2019 New Vector Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+.mx_HeaderButtons {
+    display: flex;
+}
+
+.mx_HeaderButtons::before {
+    content: "";
+    background-color: $header-divider-color;
+    margin: 2px 20px 5px 15px ;
+    border-radius: 2px;
+    width: 2px;
+}
+

res/themes/dharma/css/_dharma.scss

@@ -143,6 +143,7 @@ $roomtopic-color: #9fa9ba;
 $eventtile-meta-color: $roomtopic-color;
 
 $composer-e2e-icon-color: #c9ced6;
+$header-divider-color: #e6eaee;
 
 // ********************
 

res/themes/light/css/_base.scss

@@ -136,7 +136,7 @@ $roomtopic-color: $settings-grey-fg-color;
 $eventtile-meta-color: $roomtopic-color;
 
 $composer-e2e-icon-color: #c9ced6;
-
+$header-divider-color: #e6eaee;
 // ********************
 
 $roomtile-name-color: rgba(69, 69, 69, 0.8);

src/components/views/right_panel/HeaderButtons.js

@@ -88,7 +88,7 @@ export default class HeaderButtons extends React.Component {
 
     render() {
         // inline style as this will be swapped around in future commits
-        return <div style={{display: 'flex'}}>
+        return <div className="mx_HeaderButtons">
             { this.renderButtons() }
         </div>;
     }