Keep buttons in their associated features

Contributing all buttons in one place goes against the designs that we
set out at the beginning of the project's rewrite and that multiple of
us have been following since then.

react/features/toolbox/components/native/ToolbarButton.js

@@ -0,0 +1,62 @@
+import PropTypes from 'prop-types';
+import React from 'react';
+import { TouchableHighlight } from 'react-native';
+import { connect } from 'react-redux';
+
+import { Icon } from '../../../base/font-icons';
+
+import AbstractToolbarButton from '../AbstractToolbarButton';
+
+/**
+ * Represents a button in {@link Toolbar} on React Native.
+ *
+ * @extends AbstractToolbarButton
+ */
+class ToolbarButton extends AbstractToolbarButton {
+    /**
+     * {@code ToolbarButton} component's property types.
+     *
+     * @static
+     */
+    static propTypes = {
+        ...AbstractToolbarButton.propTypes,
+
+        /**
+         * Indicates whether this {@code ToolbarButton} is disabled.
+         */
+        disabled: PropTypes.bool
+    };
+
+    /**
+     * Renders the button of this {@code ToolbarButton}.
+     *
+     * @param {Object} children - The children, if any, to be rendered inside
+     * the button. Presumably, contains the icon of this {@code ToolbarButton}.
+     * @protected
+     * @returns {ReactElement} The button of this {@code ToolbarButton}.
+     */
+    _renderButton(children) {
+        const props = {};
+
+        'accessibilityLabel' in this.props
+            && (props.accessibilityLabel = this.props.accessibilityLabel);
+        'disabled' in this.props && (props.disabled = this.props.disabled);
+        'onClick' in this.props && (props.onPress = this._onClick);
+        'style' in this.props && (props.style = this.props.style);
+        'underlayColor' in this.props
+            && (props.underlayColor = this.props.underlayColor);
+
+        return React.createElement(TouchableHighlight, props, children);
+    }
+
+    /**
+     * Renders the icon of this {@code ToolbarButton}.
+     *
+     * @inheritdoc
+     */
+    _renderIcon() {
+        return super._renderIcon(Icon);
+    }
+}
+
+export default connect()(ToolbarButton);