Detect perf regressions and speedups automatically....

chromium_step.py

Index: chromium_step.py
===================================================================
--- chromium_step.py	(revision 24874)
+++ chromium_step.py	(working copy)
@@ -124,6 +124,15 @@
       text_list = text_list + self._result_text
     return text_list
 
+  def evaluateCommand(self, cmd):
+    # If the log processor provides a facility to evaluate its performance,
+    # call it.
+    if self._log_processor and self._log_processor.evaluateCommand:
+      return self._log_processor.evaluateCommand(cmd)
+
+    # Otherwise, report success by default.
+    return builder.SUCCESS
+
   def _CreateReportLinkIfNeccessary(self):
     if self._log_processor.ReportLink():
       self.addURL('results', "%s" % self._log_processor.ReportLink())