Enable component build for browser_context_keyed_service.

components/browser_context_keyed_service/refcounted_browser_context_keyed_service.h

 // 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.
 
 #ifndef COMPONENTS_BROWSER_CONTEXT_KEYED_SERVICE_REFCOUNTED_BROWSER_CONTEXT_KEYED_SERVICE_H_
 #define COMPONENTS_BROWSER_CONTEXT_KEYED_SERVICE_REFCOUNTED_BROWSER_CONTEXT_KEYED_SERVICE_H_
 
 #include "base/memory/ref_counted.h"
 #include "base/sequenced_task_runner_helpers.h"
+#include "components/browser_context_keyed_service/browser_context_keyed_service_export.h"
 #include "content/public/browser/browser_thread.h"
 
 class RefcountedBrowserContextKeyedService;
 
 namespace impl {
 
-struct RefcountedBrowserContextKeyedServiceTraits {
+struct BROWSER_CONTEXT_KEYED_SERVICE_EXPORT
+    RefcountedBrowserContextKeyedServiceTraits {
   static void Destruct(const RefcountedBrowserContextKeyedService* obj);
 };
 
 }  // namespace impl
 
 // Base class for refcounted objects that hang off the BrowserContext.
 //
 // The two pass shutdown described in BrowserContextKeyedService works a bit
 // differently because there could be outstanding references on other
 // threads. ShutdownOnUIThread() will be called on the UI thread, and then the
 // destructor will run when the last reference is dropped, which may or may not
 // be after the corresponding BrowserContext has been destroyed.
 //
 // Optionally, if you initialize your service with the constructor that takes a
 // thread ID, your service will be deleted on that thread. We can't use
 // content::DeleteOnThread<> directly because
 // RefcountedBrowserContextKeyedService must be one type that
 // RefcountedBrowserContextKeyedServiceFactory can use.
-class RefcountedBrowserContextKeyedService
+class BROWSER_CONTEXT_KEYED_SERVICE_EXPORT RefcountedBrowserContextKeyedService
     : public base::RefCountedThreadSafe<
           RefcountedBrowserContextKeyedService,
           impl::RefcountedBrowserContextKeyedServiceTraits> {
  public:
   // Unlike BrowserContextKeyedService, ShutdownOnUI is not optional. You must
   // do something to drop references during the first pass Shutdown() because
   // this is the only point where you are guaranteed that something is running
   // on the UI thread. The PKSF framework will ensure that this is only called
   // on the UI thread; you do not need to check for that yourself.
   virtual void ShutdownOnUIThread() = 0;
 
  protected:
   // If your service does not need to be deleted on a specific thread, use the
   // default constructor.
   RefcountedBrowserContextKeyedService();
 
   // If you need your service to be deleted on a specific thread (for example,
   // you're converting a service that used content::DeleteOnThread<IO>), then
   // use this constructor with the ID of the thread.
   explicit RefcountedBrowserContextKeyedService(
       const content::BrowserThread::ID thread_id);
 
   // The second pass destruction can happen anywhere unless you specify which
   // thread this service must be destroyed on by using the second constructor.
   virtual ~RefcountedBrowserContextKeyedService();
 
  private:
   friend struct impl::RefcountedBrowserContextKeyedServiceTraits;
   friend class base::DeleteHelper<RefcountedBrowserContextKeyedService>;
+  friend class base::RefCountedThreadSafe<RefcountedBrowserContextKeyedService,
+      impl::RefcountedBrowserContextKeyedServiceTraits>;
 
   // Do we have to delete this object on a specific thread?
   bool requires_destruction_on_thread_;
   content::BrowserThread::ID thread_id_;
 };
 
 #endif  // COMPONENTS_BROWSER_CONTEXT_KEYED_SERVICE_REFCOUNTED_BROWSER_CONTEXT_KEYED_SERVICE_H_