Room Widget Permission: Add close button assets.

Riot/Assets/Images.xcassets/Common/close_button.imageset/Contents.json

@@ -0,0 +1,23 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "filename" : "close_button.png",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "filename" : "close_button@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "universal",
+      "filename" : "close_button@3x.png",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}

Riot/Generated/Images.swift

@@ -32,6 +32,7 @@ internal enum Asset {
     internal static let adminIcon = ImageAsset(name: "admin_icon")
     internal static let backIcon = ImageAsset(name: "back_icon")
     internal static let chevron = ImageAsset(name: "chevron")
+    internal static let closeButton = ImageAsset(name: "close_button")
     internal static let disclosureIcon = ImageAsset(name: "disclosure_icon")
     internal static let group = ImageAsset(name: "group")
     internal static let logo = ImageAsset(name: "logo")