Disable flaky test SamlTest.CredentialPassingAPI for Linux

chrome/browser/chromeos/login/saml/saml_browsertest.cc

Index: chrome/browser/chromeos/login/saml/saml_browsertest.cc
diff --git a/chrome/browser/chromeos/login/saml/saml_browsertest.cc b/chrome/browser/chromeos/login/saml/saml_browsertest.cc
index 41d41edf33d76fe95b2ce9e9ee27c01a6b3bc945..0209d0b2c5315b0c19ddc7e78c8222312872e086 100644
--- a/chrome/browser/chromeos/login/saml/saml_browsertest.cc
+++ b/chrome/browser/chromeos/login/saml/saml_browsertest.cc
@@ -473,7 +473,14 @@ IN_PROC_BROWSER_TEST_F(SamlTest, MAYBE_SamlUI) {
 }
 
 // Tests the sign-in flow when the credentials passing API is used.
-IN_PROC_BROWSER_TEST_F(SamlTest, CredentialPassingAPI) {
+//
+// Flaky. See http://crbug.com/659992
+#if defined(OS_LINUX)
+#define MAYBE_CredentialPassingAPI DISABLED_CredentialPassingAPI
+#else
+#define MAYBE_CredentialPassingAPI CredentialPassingAPI
+#endif
+IN_PROC_BROWSER_TEST_F(SamlTest, MAYBE_CredentialPassingAPI) {
   fake_saml_idp()->SetLoginHTMLTemplate("saml_api_login.html");
   fake_saml_idp()->SetLoginAuthHTMLTemplate("saml_api_login_auth.html");
   StartSamlAndWaitForIdpPageLoad(kFirstSAMLUserEmail);