[Traffic Annotations] Fix MakeRelativePath() for extractor.py

extractor.py outputs relative paths rather than absolute paths (like
the clang-tool). This caused problems when running the auditor from
anywhere else than the src/ directory.

This CL updates MakeRelativePath() in the auditor to accept output
from extractor.py, even when running from another location (as it does
on CQ and waterfall).

Bug: 966883
Change-Id: I3c69d682635af6ed378bc863e1886d643a6d5c39
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1759061
Commit-Queue: Ramin Halavati <rhalavati@chromium.org>
Auto-Submit: Nicolas Ouellet-Payeur <nicolaso@chromium.org>
Reviewed-by: Ramin Halavati <rhalavati@chromium.org>
Cr-Commit-Position: refs/heads/master@{#690371}

tools/traffic_annotation/auditor/traffic_annotation_auditor.cc

@@ -129,7 +129,7 @@ std::string MakeRelativePath(const base::FilePath& base_directory,
                              file_str.length() - base_str.length() - 1);
     }
   }
-  return converted_file_path.MaybeAsASCII();
+  return file_path;
 }
 
 }  // namespace

tools/traffic_annotation/bin/linux64/traffic_annotation_auditor.sha1

-e45bc93e4e7f4e853a557ce9a074e72b490f3f23
+62dbe9751c9d8d03810f9928e29859e5af43db8d
\ No newline at end of file

tools/traffic_annotation/bin/win32/traffic_annotation_auditor.exe.sha1

-2025e4edae5aa037547cdbe111ed36e38ad9c7f9
+135da9329dc7bfe8e8056ed3976a704c777d49f3
\ No newline at end of file