Split delete modal trigger for reuse (#5740)

Spllit delete modal trigger for reuse and make emoji delete
to use this modal trigger.

webapp/components/delete_modal_trigger.jsx

@@ -0,0 +1,62 @@
+import React from 'react';
+
+import ConfirmModal from './confirm_modal.jsx';
+
+export default class DeleteModalTrigger extends React.Component {
+    constructor(props) {
+        super(props);
+        if (this.constructor === DeleteModalTrigger) {
+            throw new TypeError('Can not construct abstract class.');
+        }
+        this.handleConfirm = this.handleConfirm.bind(this);
+        this.handleCancel = this.handleCancel.bind(this);
+        this.handleOpenModal = this.handleOpenModal.bind(this);
+
+        this.state = {
+            showDeleteModal: false
+        };
+    }
+
+    handleOpenModal(e) {
+        e.preventDefault();
+
+        this.setState({
+            showDeleteModal: true
+        });
+    }
+
+    handleConfirm(e) {
+        this.props.onDelete(e);
+    }
+
+    handleCancel() {
+        this.setState({
+            showDeleteModal: false
+        });
+    }
+
+    render() {
+        return (
+            <span>
+                <a
+                    href='#'
+                    onClick={this.handleOpenModal}
+                >
+                    { this.triggerTitle }
+                </a>
+                <ConfirmModal
+                    show={this.state.showDeleteModal}
+                    title={this.modalTitle}
+                    message={this.modalMessage}
+                    confirmButton={this.modalConfirmButton}
+                    onConfirm={this.handleConfirm}
+                    onCancel={this.handleCancel}
+                />
+            </span>
+        );
+    }
+}
+
+DeleteModalTrigger.propTypes = {
+    onDelete: React.PropTypes.func.isRequired
+};