Disabling flaky OverridableProceed test.

ios/chrome/browser/ssl/ios_ssl_error_handler_unittest.mm

 // Copyright 2016 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 "ios/chrome/browser/ssl/ios_ssl_error_handler.h"
 
 #include "base/mac/bind_objc_block.h"
 #include "ios/chrome/browser/browser_state/test_chrome_browser_state.h"
 #include "ios/web/public/interstitials/web_interstitial.h"
 #import "ios/web/public/test/web_test_with_web_state.h"
@@ skipping 49 matching lines @@
   EXPECT_TRUE(web_state()->IsShowingWebInterstitial());
   web::WebInterstitial* interstitial = web_state()->GetWebInterstitial();
   EXPECT_TRUE(interstitial);
 
   // Make sure callback is called on dismissal.
   interstitial->DontProceed();
   EXPECT_TRUE(do_not_proceed_callback_called);
 }
 
 // Tests proceed with overridable error.
-TEST_F(IOSSSLErrorHandlerTest, OverridableProceed) {
+// Flaky: http://crbug.com/660343.
+TEST_F(IOSSSLErrorHandlerTest, DISABLED_OverridableProceed) {
   net::SSLInfo ssl_info;
   ssl_info.cert = cert();
   GURL url(kTestHostName);
   __block bool proceed_callback_called = false;
   IOSSSLErrorHandler::HandleSSLError(
       web_state(), net::ERR_CERT_AUTHORITY_INVALID, ssl_info, url, true,
       base::BindBlock(^(bool proceed) {
         EXPECT_TRUE(proceed);
         proceed_callback_called = true;
       }));
@@ skipping 23 matching lines @@
 
   // Make sure that interstitial is displayed.
   EXPECT_TRUE(web_state()->IsShowingWebInterstitial());
   web::WebInterstitial* interstitial = web_state()->GetWebInterstitial();
   EXPECT_TRUE(interstitial);
 
   // Make sure callback is called on dismissal.
   interstitial->DontProceed();
   EXPECT_TRUE(do_not_proceed_callback_called);
 }