1 files changed, 118 insertions, 0 deletions
diff --git a/remote/test/puppeteer/src/common/Tracing.ts b/remote/test/puppeteer/src/common/Tracing.ts
new file mode 100644
index 0000000000..ad075e9bac
--- /dev/null
+++ b/remote/test/puppeteer/src/common/Tracing.ts
@@ -0,0 +1,118 @@
+/**
+ * Copyright 2017 Google Inc. All rights reserved.
+ *
+ * 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 { assert } from './assert.js';
+import { helper } from './helper.js';
+import { CDPSession } from './Connection.js';
+
+/**
+ * @public
+ */
+export interface TracingOptions {
+  path?: string;
+  screenshots?: boolean;
+  categories?: string[];
+}
+
+/**
+ * The Tracing class exposes the tracing audit interface.
+ * @remarks
+ * You can use `tracing.start` and `tracing.stop` to create a trace file
+ * which can be opened in Chrome DevTools or {@link https://chromedevtools.github.io/timeline-viewer/ | timeline viewer}.
+ *
+ * @example
+ * ```js
+ * await page.tracing.start({path: 'trace.json'});
+ * await page.goto('https://www.google.com');
+ * await page.tracing.stop();
+ * ```
+ *
+ * @public
+ */
+export class Tracing {
+  _client: CDPSession;
+  _recording = false;
+  _path = '';
+
+  /**
+   * @internal
+   */
+  constructor(client: CDPSession) {
+    this._client = client;
+  }
+
+  /**
+   * Starts a trace for the current page.
+   * @remarks
+   * Only one trace can be active at a time per browser.
+   * @param options - Optional `TracingOptions`.
+   */
+  async start(options: TracingOptions = {}): Promise<void> {
+    assert(
+      !this._recording,
+      'Cannot start recording trace while already recording trace.'
+    );
+
+    const defaultCategories = [
+      '-*',
+      'devtools.timeline',
+      'v8.execute',
+      'disabled-by-default-devtools.timeline',
+      'disabled-by-default-devtools.timeline.frame',
+      'toplevel',
+      'blink.console',
+      'blink.user_timing',
+      'latencyInfo',
+      'disabled-by-default-devtools.timeline.stack',
+      'disabled-by-default-v8.cpu_profiler',
+      'disabled-by-default-v8.cpu_profiler.hires',
+    ];
+    const {
+      path = null,
+      screenshots = false,
+      categories = defaultCategories,
+    } = options;
+
+    if (screenshots) categories.push('disabled-by-default-devtools.screenshot');
+
+    this._path = path;
+    this._recording = true;
+    await this._client.send('Tracing.start', {
+      transferMode: 'ReturnAsStream',
+      categories: categories.join(','),
+    });
+  }
+
+  /**
+   * Stops a trace started with the `start` method.
+   * @returns Promise which resolves to buffer with trace data.
+   */
+  async stop(): Promise<Buffer> {
+    let fulfill: (value: Buffer) => void;
+    let reject: (err: Error) => void;
+    const contentPromise = new Promise<Buffer>((x, y) => {
+      fulfill = x;
+      reject = y;
+    });
+    this._client.once('Tracing.tracingComplete', (event) => {
+      helper
+        .readProtocolStream(this._client, event.stream, this._path)
+        .then(fulfill, reject);
+    });
+    await this._client.send('Tracing.end');
+    this._recording = false;
+    return contentPromise;
+  }
+}