Opt log function name

[chenBright]

What problem does this PR solve?

Issue Number:

Problem Summary:

What is changed and the side effects?

Changed: No need for gflag, just implement the function version of OnLogMessage to print the function name.

Side effects:

• Performance effects:

• Breaking backward compatibility:

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Check List:

• Please make sure your changes are compilable.
• When providing us with a new feature, it is best to add related tests.
• Please follow Contributor Covenant Code of Conduct.

[wwbmmm]

LGTM

[Copilot]

Pull Request Overview

This PR removes the log_func_name gflag and always includes function names in log messages by default.

• Updated LogSink to forward the overload without using the deprecated func parameter.
• Deprecated the log_func_name flag and simplified FlushWithoutReset to always pass _func.

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
src/butil/logging.h	Removed use of the func parameter in the second OnLogMessage overload.
src/butil/logging.cc	Marked log_func_name flag deprecated and always call the overload including function name.

Comments suppressed due to low confidence (2)

src/butil/logging.cc:155

• [nitpick] Consider adding a space after "[DEPRECATED]" in the flag help text for readability (e.g., "[DEPRECATED] Log function name...").

DEFINE_bool(log_func_name, false, "[DEPRECATED]Log function name in each log. "

src/butil/logging.cc:1387

• Add or update tests to verify that function names are always logged by default and that toggling the deprecated flag has no effect.

            bool result = (*ptr)->OnLogMessage(