Eliminate potential for flaky crash in BCKSFactory::SetTestingFactory().

components/browser_context_keyed_service/browser_context_keyed_service_factory.cc

 // Copyright (c) 2012 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 "components/browser_context_keyed_service/browser_context_keyed_service_factory.h"
 
 #include <map>
 
 #include "base/logging.h"
 #include "base/stl_util.h"
 #include "components/browser_context_keyed_service/browser_context_dependency_manager.h"
 #include "components/browser_context_keyed_service/browser_context_keyed_service.h"
 #include "content/public/browser/browser_context.h"
 
 void BrowserContextKeyedServiceFactory::SetTestingFactory(
     content::BrowserContext* context, TestingFactoryFunction testing_factory) {
   // Destroying the context may cause us to lose data about whether |context|
   // has our preferences registered on it (since the context object itself
   // isn't dead). See if we need to readd it once we've gone through normal
   // destruction.
   bool add_context = ArePreferencesSetOn(context);
 
+  // Ensure that |context| is not marked as stale (e.g., due to it aliasing an
+  // instance that was destroyed in an earlier test) in order to avoid accesses
+  // to |context| in |BrowserContextShutdown| from causing
+  // |AssertBrowserContextWasntDestroyed| to raise an error.
+  dependency_manager_->MarkBrowserContextLiveForTesting(context);
+
   // We have to go through the shutdown and destroy mechanisms because there
   // are unit tests that create a service on a context and then change the
   // testing service mid-test.
   BrowserContextShutdown(context);
   BrowserContextDestroyed(context);
 
   if (add_context)
     MarkPreferencesSetOn(context);
 
   testing_factories_[context] = testing_factory;
@@ skipping 93 matching lines @@
 
 void BrowserContextKeyedServiceFactory::SetEmptyTestingFactory(
     content::BrowserContext* context) {
   SetTestingFactory(context, NULL);
 }
 
 void BrowserContextKeyedServiceFactory::CreateServiceNow(
     content::BrowserContext* context) {
   GetServiceForBrowserContext(context, true);
 }