Disable 2 flaky content_browsertests on Mac.

content/browser/frame_host/render_frame_host_manager_browsertest.cc

 // Copyright 2013 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 <set>
 
 #include "base/command_line.h"
 #include "base/json/json_reader.h"
 #include "base/memory/ref_counted.h"
 #include "base/path_service.h"
@@ skipping 1544 matching lines @@
   }
 
   bool file_chosen() { return file_chosen_; }
 
  private:
   base::FilePath file_;
   bool file_chosen_;
 };
 
 // Test for http://crbug.com/262948.
+// Flaky on Mac. http://crbug.com/452018
+#if defined(OS_MACOSX)
+#define MAYBE_RestoreFileAccessForHistoryNavigation \
+  DISABLED_RestoreFileAccessForHistoryNavigation
+#else
+#define MAYBE_RestoreFileAccessForHistoryNavigation \
+  RestoreFileAccessForHistoryNavigation
+#endif
 IN_PROC_BROWSER_TEST_F(RenderFrameHostManagerTest,
-                       RestoreFileAccessForHistoryNavigation) {
+                       MAYBE_RestoreFileAccessForHistoryNavigation) {
   StartServer();
   base::FilePath file;
   EXPECT_TRUE(PathService::Get(base::DIR_TEMP, &file));
   file = file.AppendASCII("bar");
 
   // Navigate to url and get it to reference a file in its PageState.
   GURL url1(test_server()->GetURL("files/file_input.html"));
   NavigateToURL(shell(), url1);
   int process_id = shell()->web_contents()->GetRenderProcessHost()->GetID();
   scoped_ptr<FileChooserDelegate> delegate(new FileChooserDelegate(file));
@@ skipping 87 matching lines @@
   back_nav_load_observer.Wait();
   EXPECT_NE(process_id,
             shell()->web_contents()->GetRenderProcessHost()->GetID());
 
   // Ensure that the file access still exists in the new process ID.
   EXPECT_TRUE(ChildProcessSecurityPolicyImpl::GetInstance()->CanReadFile(
       shell()->web_contents()->GetRenderProcessHost()->GetID(), file));
 }
 
 }  // namespace content