put breadcrumbs behind feature flag

src/components/structures/LeftPanel.js

@@ -216,12 +216,17 @@ const LeftPanel = React.createClass({
             onCleared={ this.onSearchCleared }
             collapsed={this.props.collapsed} />);
 
+        let breadcrumbs;
+        if (SettingsStore.isFeatureEnabled("feature_room_breadcrumbs")) {
+            breadcrumbs = (<RoomBreadcrumbs collapsed={this.props.collapsed} />);
+        }
+
         return (
             <div className={containerClasses}>
                 { tagPanelContainer }
                 <aside className={"mx_LeftPanel dark-panel"} onKeyDown={ this._onKeyDown } onFocus={ this._onFocus } onBlur={ this._onBlur }>
                     <TopLeftMenuButton collapsed={ this.props.collapsed } />
-                    <RoomBreadcrumbs collapsed={this.props.collapsed} />
+                    { breadcrumbs }
                     { searchBox }
                     <CallPreview ConferenceHandler={VectorConferenceHandler} />
                     <RoomList

src/i18n/strings/en_EN.json

@@ -270,6 +270,7 @@
     "Failed to join room": "Failed to join room",
     "Message Pinning": "Message Pinning",
     "Custom user status messages": "Custom user status messages",
+    "Show recent room avatars above the room list": "Show recent room avatars above the room list",
     "Group & filter rooms by custom tags (refresh to apply changes)": "Group & filter rooms by custom tags (refresh to apply changes)",
     "Render simple counters in room header": "Render simple counters in room header",
     "Enable Emoji suggestions while typing": "Enable Emoji suggestions while typing",

src/settings/Settings.js

@@ -99,6 +99,12 @@ export const SETTINGS = {
         default: false,
         controller: new CustomStatusController(),
     },
+    "feature_room_breadcrumbs": {
+        isFeature: true,
+        displayName: _td("Show recent room avatars above the room list"),
+        supportedLevels: LEVELS_FEATURE,
+        default: false,
+    },
     "feature_custom_tags": {
         isFeature: true,
         displayName: _td("Group & filter rooms by custom tags (refresh to apply changes)"),