Disable WebViewFocusTest on Site Isolation FYI bots.

chrome/browser/apps/guest_view/web_view_browsertest.cc

 // Copyright 2013 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 <queue>
 
 #include "base/location.h"
 #include "base/path_service.h"
 #include "base/process/process.h"
 #include "base/single_thread_task_runner.h"
@@ skipping 335 matching lines @@
   content::WebContentsDelegate* orig_delegate_;
   bool waiting_for_decision_;
   bool expect_allow_;
   bool decision_made_;
   bool last_download_allowed_;
   scoped_refptr<content::MessageLoopRunner> message_loop_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(MockDownloadWebContentsDelegate);
 };
 
+// TODO(wjmaclean): Fix this test class at some point so it can be re-enabled on
+// the site isolation bots, and then look at re-enabling WebViewFocusTest when
+// that happens.
+// https://crbug.com/503751
 class WebViewTest : public extensions::PlatformAppBrowserTest {
  protected:
   void SetUp() override {
     if (UsesFakeSpeech()) {
       // SpeechRecognition test specific SetUp.
       fake_speech_recognition_manager_.reset(
           new content::FakeSpeechRecognitionManager());
       fake_speech_recognition_manager_->set_should_send_fake_response(true);
       // Inject the fake manager factory so that the test result is returned to
       // the web page.
@@ skipping 2031 matching lines @@
       << message_;
 }
 
 // Tests that webviews do get garbage collected.
 IN_PROC_BROWSER_TEST_F(WebViewTest, Shim_TestGarbageCollect) {
   TestHelper("testGarbageCollect", "web_view/shim", NO_TEST_SERVER);
   GetGuestViewManager()->WaitForSingleViewGarbageCollected();
 }
 
 #if defined(USE_AURA)
+// TODO(wjmaclean): when WebViewTest is re-enabled on the site-isolation
+// bots, then re-enable this test class as well.
+// https://crbug.com/503751
 class WebViewFocusTest : public WebViewTest {
  public:
   ~WebViewFocusTest() override {}
 
   void SetUpCommandLine(base::CommandLine* command_line) override {
     WebViewTest::SetUpCommandLine(command_line);
 
     command_line->AppendSwitchASCII(switches::kTouchEvents,
                                     switches::kTouchEventsEnabled);
   }
@@ skipping 107 matching lines @@
   // TODO(wjmaclean): This is fragile ... if anyone alters the location/size
   // of the webview in accept_touch_events then this may miss its target.
   FocusWaiter waiter(aura_webview);
   content::SimulateTouchPressAt(GetEmbedderWebContents(), gfx::Point(10, 10));
 
   // Wait for the TouchStart to propagate and restore focus. Test times out
   // on failure.
   waiter.Wait();
 }
 #endif