Disable the test ChromeSitePerProcessPDFTest.EmbeddedPDFInsideCrossOriginFrame on Windows.

chrome/browser/chrome_site_per_process_browsertest.cc

 // Copyright 2014 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 "base/files/file_path.h"
 #include "base/macros.h"
 #include "base/path_service.h"
 #include "base/strings/stringprintf.h"
 #include "chrome/browser/chrome_notification_types.h"
@@ skipping 302 matching lines @@
     return test_guest_view_manager_;
   }
 
  private:
   guest_view::TestGuestViewManagerFactory factory_;
   guest_view::TestGuestViewManager* test_guest_view_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeSitePerProcessPDFTest);
 };
 
+// TODO(ekaramad): This test is flaky on Windows 7. Enable it when the issue is
+// fixed ((https://crbug.com/666379).
+#if defined(OS_WIN)
+#define MAYBE_EmbeddedPDFInsideCrossOriginFrame \
+  DISABLED_EmbeddedPDFInsideCrossOriginFrame
+#else
+#define MAYBE_EmbeddedPDFInsideCrossOriginFrame \
+  EmbeddedPDFInsideCrossOriginFrame
+#endif
 // This test verifies that when navigating an OOPIF to a page with <embed>-ed
 // PDF, the guest is properly created (https://crbug.com/649856).
 IN_PROC_BROWSER_TEST_F(ChromeSitePerProcessPDFTest,
-                       EmbeddedPDFInsideCrossOriginFrame) {
+                       MAYBE_EmbeddedPDFInsideCrossOriginFrame) {
   // Navigate to a page with an <iframe>.
   GURL main_url(embedded_test_server()->GetURL("a.com", "/iframe.html"));
   ui_test_utils::NavigateToURL(browser(), main_url);
 
   // Initially, no guests are created.
   EXPECT_EQ(0U, test_guest_view_manager()->num_guests_created());
 
   // Navigate subframe to a cross-site page with an embedded PDF.
   content::WebContents* active_web_contents =
       browser()->tab_strip_model()->GetActiveWebContents();
   GURL frame_url =
       embedded_test_server()->GetURL("b.com", "/page_with_embedded_pdf.html");
 
   // Ensure the page finishes loading without crashing.
   EXPECT_TRUE(NavigateIframeToURL(active_web_contents, "test", frame_url));
 
   // Wait until the guest for PDF is created.
   test_guest_view_manager()->WaitForSingleGuestCreated();
 }