Implement debugging local unlock keys in chrome://proximity-auth.

components/proximity_auth/webui/proximity_auth_ui_delegate.h

Index: components/proximity_auth/webui/proximity_auth_ui_delegate.h
diff --git a/components/proximity_auth/webui/proximity_auth_ui_delegate.h b/components/proximity_auth/webui/proximity_auth_ui_delegate.h
index bbb3787d2444968d8aba0d1d2f7256b808cae2c3..c4c866d4a46a2c2665247d8544382af9c8a7173a 100644
--- a/components/proximity_auth/webui/proximity_auth_ui_delegate.h
+++ b/components/proximity_auth/webui/proximity_auth_ui_delegate.h
@@ -38,6 +38,9 @@ class ProximityAuthUIDelegate {
   // API requests.
   virtual cryptauth::DeviceClassifier GetDeviceClassifier() = 0;
 
+  // Returns the account id of the user.
+  virtual std::string GetAccountId() = 0;
+
   // Returns the GCMDriver instance used by Chrome.
   virtual gcm::GCMDriver* GetGCMDriver() = 0;
 };