Notify SystemURLRequestContextGetter before shutdown on iOS.

ios/chrome/browser/ios_chrome_io_thread_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/ios_chrome_io_thread.h"
+
+#include "base/message_loop/message_loop.h"
+#include "base/run_loop.h"
+#include "components/prefs/pref_registry_simple.h"
+#include "components/prefs/pref_service.h"
+#include "components/prefs/pref_service_factory.h"
+#include "components/prefs/testing_pref_store.h"
+#include "components/proxy_config/pref_proxy_config_tracker_impl.h"
+#include "components/ssl_config/ssl_config_service_manager.h"
+#include "ios/web/public/test/test_web_thread.h"
+#include "net/url_request/url_fetcher.h"
+#include "net/url_request/url_fetcher_delegate.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "testing/gtest_mac.h"
+#include "testing/platform_test.h"
+
+class IOSChromeIOThreadTest : public PlatformTest {
+ public:
+  IOSChromeIOThreadTest()
+      : loop_(base::MessageLoop::TYPE_IO),
+        ui_thread_(web::WebThread::UI, &loop_),
+        io_thread_(web::WebThread::IO, &loop_){};
+
+  ~IOSChromeIOThreadTest() override {}
+
+  void SetUp() override { DCHECK_CURRENTLY_ON(web::WebThread::UI); }
+
+  void TearDown() override { DCHECK_CURRENTLY_ON(web::WebThread::UI); }
+
+ private:
+  base::MessageLoop loop_;
+  web::TestWebThread ui_thread_;
+  web::TestWebThread io_thread_;
+};
+
+// A delegate interface for users of URLFetcher.
+class TestURLFetcherDelegate : public net::URLFetcherDelegate {

[mmenke, 2016/07/27 17:23:45]

This should be in an anonymous namespace (I'd put the whole file in one, but
only this needs to be in one)

[mef, 2016/07/27 18:04:27]

Done.

+ public:
+  TestURLFetcherDelegate() {}
+  ~TestURLFetcherDelegate() override {}
+
+  // net::URLFetcherDelegate implementation.
+  void OnURLFetchComplete(const net::URLFetcher* source) override {}
+};
+
+TEST_F(IOSChromeIOThreadTest, AssertNoUrlRequests) {
+  PrefServiceFactory pref_service_factory;
+  pref_service_factory.set_user_prefs(
+      make_scoped_refptr(new TestingPrefStore()));
+
+  scoped_refptr<PrefRegistrySimple> pref_registry = new PrefRegistrySimple;
+  PrefProxyConfigTrackerImpl::RegisterPrefs(pref_registry.get());
+  ssl_config::SSLConfigServiceManager::RegisterPrefs(pref_registry.get());
+
+  std::unique_ptr<PrefService> pref_service(
+      pref_service_factory.Create(pref_registry.get()));
+
+  // Create and init IOSChromeIOThread.
+  std::unique_ptr<IOSChromeIOThread> ios_chrome_io_thread(
+      new IOSChromeIOThread(pref_service.get(), nullptr));
+  web::WebThreadDelegate* web_thread_delegate =
+      static_cast<web::WebThreadDelegate*>(ios_chrome_io_thread.get());

[mmenke, 2016/07/27 17:23:45]

This is weird.  I guess it's needed because IOSChromeIOThread override public
methods with private ones?

[mef, 2016/07/27 18:04:27]

Exactly.

+  web_thread_delegate->Init();
+
+  // Create and start fetcher.
+  TestURLFetcherDelegate fetcher_delegate;
+  std::unique_ptr<net::URLFetcher> fetcher = net::URLFetcher::Create(
+      GURL("http://example.com"), net::URLFetcher::GET, &fetcher_delegate);
+  fetcher->SetRequestContext(
+      ios_chrome_io_thread->system_url_request_context_getter());
+  fetcher->Start();
+  base::RunLoop().RunUntilIdle();

[mmenke, 2016/07/27 17:23:46]

What guarantee do we have that the fetcher wont complete when we do this? 
Should we do URLRequestFailedJob::AddUrlHandler() and
URLRequestFailedJob::GetMockHttpUrl(ERR_IO_PENDING)?

[mef, 2016/07/27 18:04:27]

Done.

+  // Verify that there is no AssertNoUrlRequests triggered during CleanUp.
+  web_thread_delegate->CleanUp();
+}