Add a basic error boundary for the entire app

This adds a basic error boundary around the entire app to catch errors during
rendering and present the user with the options on how to proceed. This is not
implemented as a modal so that it could be used selectively in portions of the
app as well, such as just the `RoomView`.

Fixes https://github.com/vector-im/riot-web/issues/11009

src/components/views/elements/ErrorBoundary.js

@@ -0,0 +1,104 @@
+/*
+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 sdk from '../../../index';
+import { _t } from '../../../languageHandler';
+import MatrixClientPeg from '../../../MatrixClientPeg';
+import PlatformPeg from '../../../PlatformPeg';
+import Modal from '../../../Modal';
+
+/**
+ * This error boundary component can be used to wrap large content areas and
+ * catch exceptions during rendering in the component tree below them.
+ */
+export default class ErrorBoundary extends React.PureComponent {
+    constructor(props) {
+        super(props);
+
+        this.state = {
+            error: null,
+        };
+    }
+
+    static getDerivedStateFromError(error) {
+        // Side effects are not permitted here, so we only update the state so
+        // that the next render shows an error message.
+        return { error };
+    }
+
+    componentDidCatch(error, { componentStack }) {
+        // Browser consoles are better at formatting output when native errors are passed
+        // in their own `console.error` invocation.
+        console.error(error);
+        console.error(
+            "The above error occured while React was rendering the following components:",
+            componentStack,
+        );
+    }
+
+    _onClearCacheAndReload = () => {
+        if (!PlatformPeg.get()) return;
+
+        MatrixClientPeg.get().stopClient();
+        MatrixClientPeg.get().store.deleteAllData().done(() => {
+            PlatformPeg.get().reload();
+        });
+    };
+
+    _onBugReport = () => {
+        const BugReportDialog = sdk.getComponent("dialogs.BugReportDialog");
+        if (!BugReportDialog) {
+            return;
+        }
+        Modal.createTrackedDialog('Bug Report Dialog', '', BugReportDialog, {});
+    };
+
+    render() {
+        if (this.state.error) {
+            const AccessibleButton = sdk.getComponent('elements.AccessibleButton');
+            const newIssueUrl = "https://github.com/vector-im/riot-web/issues/new";
+            return <div className="mx_ErrorBoundary">
+                <div className="mx_ErrorBoundary_body">
+                    <h1>{_t("Something went wrong!")}</h1>
+                    <p>{_t(
+                        "Please <newIssueLink>create a new issue</newIssueLink> " +
+                        "on GitHub so that we can investigate this bug.", {}, {
+                            newIssueLink: (sub) => {
+                                return <a target="_blank" rel="noreferrer noopener" href={newIssueUrl}>{ sub }</a>;
+                            },
+                        },
+                    )}</p>
+                    <p>{_t(
+                        "If you've submitted a bug via GitHub, debug logs can help " +
+                        "us track down the problem. Debug logs contain application " +
+                        "usage data including your username, the IDs or aliases of " +
+                        "the rooms or groups you have visited and the usernames of " +
+                        "other users. They do not contain messages.",
+                    )}</p>
+                    <AccessibleButton onClick={this._onBugReport} kind='primary'>
+                        {_t("Submit debug logs")}
+                    </AccessibleButton>
+                    <AccessibleButton onClick={this._onClearCacheAndReload} kind='danger'>
+                        {_t("Clear cache and reload")}
+                    </AccessibleButton>
+                </div>
+            </div>;
+        }
+
+        return this.props.children;
+    }
+}