NoState Prefetch: nostate prefetch browser tests.

chrome/browser/prerender/prerender_manager_factory.h

Index: chrome/browser/prerender/prerender_manager_factory.h
diff --git a/chrome/browser/prerender/prerender_manager_factory.h b/chrome/browser/prerender/prerender_manager_factory.h
index 46e7e67f2db756bb316e4ada0a1de322763340b4..e6a35f65bf3d62f4b527df823fe40d03397192f2 100644
--- a/chrome/browser/prerender/prerender_manager_factory.h
+++ b/chrome/browser/prerender/prerender_manager_factory.h
@@ -30,6 +30,22 @@ class PrerenderManagerFactory : public BrowserContextKeyedServiceFactory {
 
   static PrerenderManagerFactory* GetInstance();
 
+  // Sets a global TestingFactoryFunction that will be used to create
+  // PrerenderManagers for all BrowserContexts.
+  //
+  // In-process browser tests cannot use KeyedServiceFactory::SetTestingFactory
+  // to override the PrerenderManagerFactory. The test instance is started
+  // before there is a browser or profile and so it is not possible to
+  // SetTestingFactory. By the time the first testing hook after browser
+  // creation is called (content::BrowserTestBase::SetUpOnMainThread), the
+  // PrerenderManager instance has already by created (eg, by the prerender tab
+  // helper), and it is too late. This testing_create_function overrides
+  // PrerenderManager creation for all profiles.
+  static void set_testing_create_function(
+      TestingFactoryFunction create_function) {
+    testing_create_function_ = create_function;
+  }
+
  private:
   friend struct base::DefaultSingletonTraits<PrerenderManagerFactory>;
 
@@ -41,6 +57,8 @@ class PrerenderManagerFactory : public BrowserContextKeyedServiceFactory {
       content::BrowserContext* profile) const override;
   content::BrowserContext* GetBrowserContextToUse(
       content::BrowserContext* context) const override;
+
+  static TestingFactoryFunction testing_create_function_;
 };
 
 }  // namespace prerender