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

components/browser_context_keyed_service/browser_context_keyed_base_factory.h

Index: components/browser_context_keyed_service/browser_context_keyed_base_factory.h
diff --git a/components/browser_context_keyed_service/browser_context_keyed_base_factory.h b/components/browser_context_keyed_service/browser_context_keyed_base_factory.h
index 36f282999484bc0950460b55af1f6998e5f34c8f..4d8e95a82fbff96b0c183a1e70cdeb43dc3cbbb3 100644
--- a/components/browser_context_keyed_service/browser_context_keyed_base_factory.h
+++ b/components/browser_context_keyed_service/browser_context_keyed_base_factory.h
@@ -111,6 +111,12 @@ BrowserContextKeyedBaseFactory
   // Mark context as Preferences set.
   void MarkPreferencesSetOn(content::BrowserContext* context);
 
+  // Which BrowserContextDependencyManager we should communicate with.
+  // In real code, this will always be
+  // BrowserContextDependencyManager::GetInstance(), but unit tests will want
+  // to use their own copy.
+  BrowserContextDependencyManager* dependency_manager_;
+
  private:
   friend class BrowserContextDependencyManager;
   friend class BrowserContextDependencyManagerUnittests;
@@ -132,12 +138,6 @@ BrowserContextKeyedBaseFactory
   // now for when we're creating the context.
   virtual void CreateServiceNow(content::BrowserContext* context) = 0;
 
-  // Which BrowserContextDependencyManager we should communicate with.
-  // In real code, this will always be
-  // BrowserContextDependencyManager::GetInstance(), but unit tests will want
-  // to use their own copy.
-  BrowserContextDependencyManager* dependency_manager_;
-
   // BrowserContexts that have this service's preferences registered on them.
   std::set<const content::BrowserContext*> registered_preferences_;