[ios] Implements more of ChromiumBrowserProvider.

ios/chrome/browser/providers/chromium_browser_provider.h

Index: ios/chrome/browser/providers/chromium_browser_provider.h
diff --git a/ios/chrome/browser/providers/chromium_browser_provider.h b/ios/chrome/browser/providers/chromium_browser_provider.h
index 904a9196d752572a52a808b3d199c21fed3a25ba..947b2aed581dd356dbddaa5e2b9aff30ad8b5389 100644
--- a/ios/chrome/browser/providers/chromium_browser_provider.h
+++ b/ios/chrome/browser/providers/chromium_browser_provider.h
@@ -12,13 +12,23 @@ class ChromiumBrowserProvider : public ios::ChromeBrowserProvider {
   ChromiumBrowserProvider();
   ~ChromiumBrowserProvider() override;
 
- private:
   // ChromeBrowserProvider implementation
+  ios::SigninErrorProvider* GetSigninErrorProvider() override;
+  ios::SigninResourcesProvider* GetSigninResourcesProvider() override;
+  void SetChromeIdentityServiceForTesting(
+      std::unique_ptr<ios::ChromeIdentityService> service) override;
+  ios::ChromeIdentityService* GetChromeIdentityService() override;
+  void InitializeCastService(id main_tab_model) const override;
+  void AttachTabHelpers(web::WebState* web_state, id tab) const override;
   VoiceSearchProvider* GetVoiceSearchProvider() const override;
   id<LogoVendor> CreateLogoVendor(ios::ChromeBrowserState* browser_state,
                                   id<UrlLoader> loader) const override
       NS_RETURNS_RETAINED;
 
+ private:
+  std::unique_ptr<ios::SigninErrorProvider> signin_error_provider_;
+  std::unique_ptr<ios::SigninResourcesProvider> signin_resources_provider_;
+  std::unique_ptr<ios::ChromeIdentityService> chrome_identity_service_;
   std::unique_ptr<VoiceSearchProvider> voice_search_provider_;
 };