[Extensions] Add a developerPrivate.deleteExtensionErrors function

Add a developerPrivate API function for removing extension errors.

BUG=TBD

Review URL: https://codereview.chromium.org/1014323003

Cr-Commit-Position: refs/heads/master@{#321673}
diff --git a/extensions/browser/extension_function_histogram_value.h b/extensions/browser/extension_function_histogram_value.h
index 3cbb60b..f3d0785 100644
--- a/extensions/browser/extension_function_histogram_value.h
+++ b/extensions/browser/extension_function_histogram_value.h
@@ -1040,6 +1040,7 @@
   DEVELOPERPRIVATE_GETEXTENSIONINFO,
   FILEMANAGERPRIVATE_ENABLEEXTERNALFILESCHEME,
   DEVELOPERPRIVATE_UPDATEEXTENSIONCONFIGURATION,
+  DEVELOPERPRIVATE_DELETEEXTENSIONERRORS,
   // Last entry: Add new entries above and ensure to update
   // tools/metrics/histograms/histograms.xml.
   ENUM_BOUNDARY