Implement dialpad view controller

Riot/Modules/Call/Dialpad/Views/DialpadActionButton.swift

@@ -0,0 +1,39 @@
+// 
+// Copyright 2020 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.
+//
+
+import UIKit
+
+/// Dialpad action button type
+@objc enum DialpadActionButtonType: Int {
+    case backspace
+    case call
+}
+
+/// Action button class for Dialpad screen
+class DialpadActionButton: DialpadButton {
+
+    var type: DialpadActionButtonType = .backspace
+    
+    override func update(theme: Theme) {
+        switch type {
+        case .backspace:
+            backgroundColor = theme.warningColor
+        case .call:
+            backgroundColor = theme.tintColor
+        }
+    }
+
+}