[RN] Add chat functionality

Co-authored-by: DimaG <dgeorgiev06@gmail.com>

react/features/chat/components/AbstractChatMessage.js

@@ -0,0 +1,48 @@
+// @flow
+
+import { PureComponent } from 'react';
+
+import { getAvatarURLByParticipantId } from '../../base/participants';
+
+/**
+ * The type of the React {@code Component} props of {@code AbstractChatMessage}.
+ */
+export type Props = {
+
+    /**
+     * The URL of the avatar of the participant.
+     */
+    _avatarURL: string,
+
+    /**
+     * The representation of a chat message.
+     */
+    message: Object,
+
+    /**
+     * Invoked to receive translated strings.
+     */
+    t: Function
+};
+
+/**
+ * Abstract component to display a chat message.
+ */
+export default class AbstractChatMessage<P: Props> extends PureComponent<P> {}
+
+/**
+ * Maps part of the Redux state to the props of this component.
+ *
+ * @param {Object} state - The Redux state.
+ * @param {Props} ownProps - The own props of the component.
+ * @returns {{
+ *     _avatarURL: string
+ * }}
+ */
+export function _mapStateToProps(state: Object, ownProps: Props) {
+    const { message } = ownProps;
+
+    return {
+        _avatarURL: getAvatarURLByParticipantId(state, message.user._id)
+    };
+}