[Signin] Factor out a helper class to load a continue URL once Sync is configured.

chrome/browser/ui/sync/one_click_signin_helper.h

Index: chrome/browser/ui/sync/one_click_signin_helper.h
diff --git a/chrome/browser/ui/sync/one_click_signin_helper.h b/chrome/browser/ui/sync/one_click_signin_helper.h
index e566edb0a101f75fd0f49b9b775f2120830b14da..c8adad4fd57abb6737c43954a338801b53f26510 100644
--- a/chrome/browser/ui/sync/one_click_signin_helper.h
+++ b/chrome/browser/ui/sync/one_click_signin_helper.h
@@ -44,8 +44,7 @@ class URLRequest;
 // more about what this means.
 class OneClickSigninHelper
     : public content::WebContentsObserver,
-      public content::WebContentsUserData<OneClickSigninHelper>,
-      public ProfileSyncServiceObserver {
+      public content::WebContentsUserData<OneClickSigninHelper> {
  public:
   // Represents user's decision about sign in process.
   enum AutoAccept {
@@ -253,8 +252,6 @@ class OneClickSigninHelper
   FRIEND_TEST_ALL_PREFIXES(OneClickSigninHelperTest, SigninFailed);
   FRIEND_TEST_ALL_PREFIXES(OneClickSigninHelperTest,
                            CleanTransientStateOnNavigate);
-  FRIEND_TEST_ALL_PREFIXES(OneClickSigninHelperTest,
-                           RemoveObserverFromProfileSyncService);
   FRIEND_TEST_ALL_PREFIXES(OneClickSigninHelperIOTest, CanOfferOnIOThread);
   FRIEND_TEST_ALL_PREFIXES(OneClickSigninHelperIOTest,
                            CanOfferOnIOThreadIncognito);
@@ -342,10 +339,6 @@ class OneClickSigninHelper
       const content::FrameNavigateParams& params) OVERRIDE;
   virtual void DidStopLoading(
       content::RenderViewHost* render_view_host) OVERRIDE;
-  virtual void WebContentsDestroyed(content::WebContents* contents) OVERRIDE;
-
-  // ProfileSyncServiceObserver.
-  virtual void OnStateChanged() OVERRIDE;
 
   OneClickSigninSyncStarter::Callback CreateSyncStarterCallback();