Histograms.xml python script housekeeping

tools/metrics/histograms/validate_format.py

Index: tools/metrics/histograms/validate_format.py
diff --git a/tools/metrics/histograms/validate_format.py b/tools/metrics/histograms/validate_format.py
index 4ca3e0873b66ac646e0973bbfa1a4ccef1d312d6..3977bc0c5926474fb7f808c18568a1f2608a8a34 100755
--- a/tools/metrics/histograms/validate_format.py
+++ b/tools/metrics/histograms/validate_format.py
@@ -5,14 +5,17 @@
 
 """Verifies that the histograms XML file is well-formatted."""
 
-import extract_histograms
-import os.path
+import os
+import sys
+
+sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'common'))
+import path_util
 
+import extract_histograms
 
 def main():
   # This will raise an exception if the file is not well-formatted.
-  xml_file = os.path.join(os.path.dirname(os.path.realpath(__file__)),
-                          'histograms.xml')
+  xml_file = path_util.GetHistogramsFile()
   histograms = extract_histograms.ExtractHistograms(xml_file)