Disable flaky DevToolsBeforeUnloadTest.TestUndockedDevToolsClose on Linux

chrome/browser/devtools/devtools_sanity_browsertest.cc

 // Copyright (c) 2012 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 <stddef.h>
 
 #include <memory>
 
 #include "base/bind.h"
 #include "base/cancelable_callback.h"
@@ skipping 711 matching lines @@
 // we try to close the inspected browser.
 IN_PROC_BROWSER_TEST_F(DevToolsBeforeUnloadTest,
                        TestDockedDevToolsInspectedBrowserClose) {
   RunBeforeUnloadSanityTest(true, base::Bind(
       &DevToolsBeforeUnloadTest::CloseInspectedBrowser,
       base::Unretained(this)));
 }
 
 // Tests that BeforeUnload event gets called on undocked devtools if
 // we try to close them.
-// Flaky on Windows.  http://crbug.com/702171
-#if defined(OS_WIN)
+// Flaky on Windows and Linux.  http://crbug.com/702171
+#if defined(OS_WIN) || defined(OS_LINUX)
 #define MAYBE_TestUndockedDevToolsClose DISABLED_TestUndockedDevToolsClose
 #else
 #define MAYBE_TestUndockedDevToolsClose TestUndockedDevToolsClose
 #endif
 
 IN_PROC_BROWSER_TEST_F(DevToolsBeforeUnloadTest,
                        MAYBE_TestUndockedDevToolsClose) {
   RunBeforeUnloadSanityTest(false, base::Bind(
       &DevToolsBeforeUnloadTest::CloseDevToolsWindowAsync,
       base::Unretained(this)), false);
@@ skipping 805 matching lines @@
   RunTestFunction(window, "testWindowInitializedOnNavigateBack");
 
   DevToolsWindowTesting::CloseDevToolsWindowSync(window);
   content::WebUIControllerFactory::UnregisterFactoryForTesting(&test_factory);
 }
 
 // Tests scripts panel showing.
 IN_PROC_BROWSER_TEST_F(DevToolsSanityTest, TestDevToolsSharedWorker) {
   RunTest("testDevToolsSharedWorker", url::kAboutBlankURL);
 }