Move all the ContextMenu semantic helper (ARIA) components out to separate modules

Signed-off-by: Michael Telatynski <7t3chguy@gmail.com>

src/accessibility/context_menu/ContextMenuButton.tsx

@@ -0,0 +1,51 @@
+/*
+Copyright 2015, 2016 OpenMarket Ltd
+Copyright 2018 New Vector Ltd
+Copyright 2019 The Matrix.org Foundation C.I.C.
+
+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 React from "react";
+
+import AccessibleButton, {IProps as IAccessibleButtonProps} from "../../components/views/elements/AccessibleButton";
+
+interface IProps extends IAccessibleButtonProps {
+    label?: string;
+    // whether or not the context menu is currently open
+    isExpanded: boolean;
+}
+
+// Semantic component for representing the AccessibleButton which launches a <ContextMenu />
+export const ContextMenuButton: React.FC<IProps> = ({
+    label,
+    isExpanded,
+    children,
+    onClick,
+    onContextMenu,
+    ...props
+}) => {
+    return (
+        <AccessibleButton
+            {...props}
+            onClick={onClick}
+            onContextMenu={onContextMenu || onClick}
+            title={label}
+            aria-label={label}
+            aria-haspopup={true}
+            aria-expanded={isExpanded}
+        >
+            { children }
+        </AccessibleButton>
+    );
+};