Disable DownloadExtensionTest_Download_FileSystemURL on Mac

chrome/browser/extensions/api/downloads/downloads_api_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.
 
 // Disable everything on windows only. http://crbug.com/306144
 #ifndef OS_WIN
 
 #include <algorithm>
 
 #include "base/file_util.h"
@@ skipping 2275 matching lines @@
   ASSERT_TRUE(WaitFor(downloads::OnChanged::kEventName,
                       base::StringPrintf(
                           "[{\"id\": %d,"
                           "  \"error\": {\"current\":\"USER_CANCELED\"},"
                           "  \"state\": {"
                           "    \"previous\": \"in_progress\","
                           "    \"current\": \"interrupted\"}}]",
                           result_id)));
 }
 
+// flaky on mac: crbug.com/392288
+#if defined(OS_MACOSX)
+#define MAYBE_DownloadExtensionTest_Download_FileSystemURL \
+        DISABLED_DownloadExtensionTest_Download_FileSystemURL
+#else
+#define MAYBE_DownloadExtensionTest_Download_FileSystemURL \
+        DownloadExtensionTest_Download_FileSystemURL
+#endif
+
 // Test downloading filesystem: URLs.
 // NOTE: chrome disallows creating HTML5 FileSystem Files in incognito.
 IN_PROC_BROWSER_TEST_F(DownloadExtensionTest,
-                       DownloadExtensionTest_Download_FileSystemURL) {
+                       MAYBE_DownloadExtensionTest_Download_FileSystemURL) {
   static const char* kPayloadData = "on the record\ndata";
   GoOnTheRecord();
   LoadExtension("downloads_split");
 
   const std::string download_url = "filesystem:" + GetExtensionURL() +
     "temporary/on_record.txt";
 
   // Setup a file in the filesystem which we can download.
   ASSERT_TRUE(HTML5FileWriter::CreateFileForTesting(
       BrowserContext::GetDefaultStoragePartition(browser()->profile())->
@@ skipping 1783 matching lines @@
   EXPECT_EQ(downloads::FILENAME_CONFLICT_ACTION_PROMPT, conflict_action);
   EXPECT_FALSE(warnings.empty());
   EXPECT_EQ(ExtensionWarning::kDownloadFilenameConflict,
             warnings.begin()->warning_type());
   EXPECT_EQ("incumbent", warnings.begin()->extension_id());
 }
 
 }  // namespace extensions
 
 #endif  // http://crbug.com/3061144