Disable PolicyTest.DisableScreenshotsFile test due to being flaky.

chrome/browser/policy/policy_browsertest.cc

Index: chrome/browser/policy/policy_browsertest.cc
diff --git a/chrome/browser/policy/policy_browsertest.cc b/chrome/browser/policy/policy_browsertest.cc
index 3bef5a61ae4cfd6ad74416f908c30df21ede6bb0..6b7dcc46c5b3322ffc8a21d9faca30b727d14dfc 100644
--- a/chrome/browser/policy/policy_browsertest.cc
+++ b/chrome/browser/policy/policy_browsertest.cc
@@ -2570,14 +2570,8 @@ IN_PROC_BROWSER_TEST_F(PolicyTest, FullscreenAllowedApp) {
 
 #if defined(OS_CHROMEOS)
 
-// Flaky http://crbug.com/476964
-#if defined(MEMORY_SANITIZER)
-#define MAYBE_DisableScreenshotsFile DISABLED_DisableScreenshotsFile
-#else
-#define MAYBE_DisableScreenshotsFile DisableScreenshotsFile
-#endif
-
-IN_PROC_BROWSER_TEST_F(PolicyTest, MAYBE_DisableScreenshotsFile) {
+// Flaky on MSan (crbug.com/476964) and regular Chrome OS (crbug.com/645769).
+IN_PROC_BROWSER_TEST_F(PolicyTest, DISABLED_DisableScreenshotsFile) {
   int screenshot_count = CountScreenshots();
 
   // Make sure screenshots are counted correctly.