[ios] Automatically fail any WebTest whose render process crashes.

ios/web/public/test/web_test.h

 // 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.
 
 #ifndef IOS_WEB_PUBLIC_TEST_WEB_TEST_H_
 #define IOS_WEB_PUBLIC_TEST_WEB_TEST_H_
 
 #include "ios/web/public/test/fakes/test_browser_state.h"
 #include "ios/web/public/test/scoped_testing_web_client.h"
 #include "ios/web/public/test/test_web_thread_bundle.h"
 #include "testing/platform_test.h"
 
 namespace web {
 
 class BrowserState;
+class RendererCrashObserver;
 class TestWebClient;
 
 // A test fixture for web tests that need a minimum environment set up that
 // mimics a web embedder.
 class WebTest : public PlatformTest {
  protected:
   WebTest();
   ~WebTest() override;
 
   // PlatformTest methods.
   void SetUp() override;
   void TearDown() override;
 
   // Returns the WebClient that is used for testing.
   TestWebClient* GetWebClient();
 
   // Returns the BrowserState that is used for testing.
   virtual BrowserState* GetBrowserState();
 
+  // If called with |true|, prevents the test fixture from automatically failing
+  // when a render process crashes during the test.  This is useful for tests
+  // that intentionally crash the render process.

[Eugene But (OOO till 7-30), 2017/02/01 16:43:04]

Would it be helpful to document that default state is false?

[rohitrao (ping after 24h), 2017/02/01 18:22:59]

Done.

+  void AllowRenderProcessCrashesDuringTesting(bool allow);

[Eugene But (OOO till 7-30), 2017/02/01 16:43:04]

Should this be prefixed with Set (e.g.
SetAllowsRenderProcessCrashesDuringTesting)?

[rohitrao (ping after 24h), 2017/02/01 18:22:59]

Done.

+
  private:
   // The WebClient used in tests.
   ScopedTestingWebClient web_client_;
   // The threads used for testing.
   web::TestWebThreadBundle thread_bundle_;
   // The browser state used in tests.
   TestBrowserState browser_state_;
+
+  // Triggers test failures if a renderer process dies during the test.
+  std::unique_ptr<RendererCrashObserver> renderer_crash_observer_;
 };
 
 }  // namespace web
 
 #endif  // IOS_WEB_PUBLIC_TEST_WEB_TEST_H_