Media Session: add test for crash with command send on iframe during unload.

content/browser/media/session/media_session_service_impl_browsertest.cc

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/command_line.h"
+#include "content/public/test/content_browser_test.h"
+#include "content/public/test/content_browser_test_utils.h"
+#include "content/shell/browser/shell.h"
+
+namespace content {
+
+class MediaSessionServiceImplBrowserTest : public ContentBrowserTest {
+ protected:
+  void SetUpCommandLine(base::CommandLine* command_line) override {
+    ContentBrowserTest::SetUpCommandLine(command_line);
+    command_line->AppendSwitchASCII("--enable-blink-features", "MediaSession");
+  }
+};
+
+// Two windows from the same BrowserContext.
+IN_PROC_BROWSER_TEST_F(MediaSessionServiceImplBrowserTest,
+                       CrashMessageOnUnload) {
+  NavigateToURL(shell(), GetTestUrl("media/session", "embedder.html"));
+  // Navigate to a chrome:// URL to avoid render process re-use.
+  NavigateToURL(shell(), GURL("chrome://flags"));
+  // Should not crash.
+}
+
+}  // namespace content