Add UMA metrics for supervised users enabling and disabling extensions

This CL adds UMA metrics for supervised users enabling and disabling
extensions that have already been approved by the parent.

Bug: 1022620
Change-Id: Ic66abfd6a6468fc0c12bf30faf268c626286a9ec
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2199407
Commit-Queue: Toby Huang <[email protected]>
Reviewed-by: Dan S <[email protected]>
Reviewed-by: Brian White <[email protected]>
Reviewed-by: Devlin <[email protected]>
Auto-Submit: Toby Huang <[email protected]>
Cr-Commit-Position: refs/heads/master@{#769524}
diff --git a/chrome/browser/supervised_user/supervised_user_service.h b/chrome/browser/supervised_user/supervised_user_service.h
index d1fbed1..8bae30f5 100644
--- a/chrome/browser/supervised_user/supervised_user_service.h
+++ b/chrome/browser/supervised_user/supervised_user_service.h
@@ -221,6 +221,8 @@
   bool CanInstallExtensions() const;
 
   bool IsExtensionAllowed(const extensions::Extension& extension) const;
+
+  void RecordExtensionEnablementUmaMetrics(bool enabled) const;
 #endif  // BUILDFLAG(ENABLE_EXTENSIONS)
 
  private: