Introduce Identity Service and its initial usage

chrome/browser/extensions/api/identity/identity_get_profile_user_info_function.h

Index: chrome/browser/extensions/api/identity/identity_get_profile_user_info_function.h
diff --git a/chrome/browser/extensions/api/identity/identity_get_profile_user_info_function.h b/chrome/browser/extensions/api/identity/identity_get_profile_user_info_function.h
index 2d3b434705d3c499888efb75a8a70af0318bdae3..c2a1ce9137aef82877d2f2973a4cc62b1e1f74d8 100644
--- a/chrome/browser/extensions/api/identity/identity_get_profile_user_info_function.h
+++ b/chrome/browser/extensions/api/identity/identity_get_profile_user_info_function.h
@@ -6,7 +6,9 @@
 #define CHROME_BROWSER_EXTENSIONS_API_IDENTITY_IDENTITY_GET_PROFILE_USER_INFO_FUNCTION_H_
 
 #include "chrome/browser/extensions/chrome_extension_function.h"
+#include "components/signin/core/account_id/account_id.h"
 #include "extensions/browser/extension_function_histogram_value.h"
+#include "services/identity/public/interfaces/identity_manager.mojom.h"
 
 namespace extensions {
 
@@ -20,9 +22,12 @@ class IdentityGetProfileUserInfoFunction
 
  private:
   ~IdentityGetProfileUserInfoFunction() override;
+  void OnReceivedPrimaryAccountId(const base::Optional<AccountId>& account_id);
 
   // UIThreadExtensionFunction implementation.
   ExtensionFunction::ResponseAction Run() override;
+
+  identity::mojom::IdentityManagerPtr identity_manager_;
 };
 
 }  // namespace extensions