[sheriff] Disable PDFExtensionTestWithTestGuestViewManager.CSPDoesNotBlockEmbedStyles

The test is flaky on win and linux

TBR=eirage@chromium.org
NOTRY=true

Bug: 1150197
Change-Id: I8f7913aac1dcb45facd26212cb9985702438e39c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2637257Reviewed-by: Xida Chen <xidachen@chromium.org>
Reviewed-by: Ella Ge <eirage@chromium.org>
Commit-Queue: Xida Chen <xidachen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#844803}

chrome/browser/pdf/pdf_extension_test.cc

@@ -552,8 +552,14 @@ IN_PROC_BROWSER_TEST_P(PDFExtensionTestWithTestGuestViewManager,
 // This test verifies that when a PDF is served with a restrictive
 // Content-Security-Policy, the embed tag is still sized correctly.
 // Regression test for https://crbug.com/271452.
+// Flaky on win and linux: crbug.com/1150197
+#if defined(OS_WIN) || defined(OS_LINUX)
+#define MAYBE_CSPDoesNotBlockEmbedStyles DISABLED_CSPDoesNotBlockEmbedStyles
+#else
+#define MAYBE_CSPDoesNotBlockEmbedStyles CSPDoesNotBlockEmbedStyles
+#endif
 IN_PROC_BROWSER_TEST_P(PDFExtensionTestWithTestGuestViewManager,
-                       CSPDoesNotBlockEmbedStyles) {
+                       MAYBE_CSPDoesNotBlockEmbedStyles) {
   GURL main_url(embedded_test_server()->GetURL("/pdf/test-csp.pdf"));
   ui_test_utils::NavigateToURL(browser(), main_url);
   auto* embedder_web_contents = GetActiveWebContents();