Disable EarlGrey tests that break using webview in current webstate.

ios/chrome/browser/metrics/tab_usage_recorder_egtest.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.
 
 #import <EarlGrey/EarlGrey.h>
 #import <XCTest/XCTest.h>
 
 #include "base/mac/bind_objc_block.h"
 #include "base/memory/ptr_util.h"
 #include "base/strings/stringprintf.h"
@@ skipping 497 matching lines @@
                                      TabUsageRecorder::LOAD_SUCCESS, 1,
                                      failureBlock);
   histogramTester.ExpectUniqueSample(kDidUserWaitForEvictedTabReload,
                                      TabUsageRecorder::USER_WAITED, 1,
                                      failureBlock);
   histogramTester.ExpectTotalCount(kEvictedTabReloadTime, 1, failureBlock);
 }
 
 // Verify correct recording of metrics when the reloading of an evicted tab
 // fails.
-- (void)testEvictedTabReloadFailure {
+// TODO(crbug.com/684987): Re-enable this test.
+- (void)DISABLED_testEvictedTabReloadFailure {
   web::test::SetUpFileBasedHttpServer();
   chrome_test_util::HistogramTester histogramTester;
   FailureBlock failureBlock = ^(NSString* error) {
     GREYFail(error);
   };
 
   // This URL is purposely invalid so it triggers a navigation error.
   GURL invalidURL(kTestUrl1);
 
   chrome_test_util::OpenNewTab();
@@ skipping 429 matching lines @@
     [[GREYUIThreadExecutor sharedInstance] drainUntilIdle];
   }
   // The deleted tabs are purged during foregrounding and backgrounding.
   chrome_test_util::SimulateTabsBackgrounding();
   // Make sure |evicted_tabs_| purged the deleted tabs.
   int evicted = chrome_test_util::GetEvictedMainTabCount();
   GREYAssertEqual(evicted, 0, @"Check number of evicted tabs");
 }
 
 @end