Hide console log messages for imported WPT tests

content/shell/test_runner/web_test_delegate.h

Index: content/shell/test_runner/web_test_delegate.h
diff --git a/content/shell/test_runner/web_test_delegate.h b/content/shell/test_runner/web_test_delegate.h
index 53f803e46e37b0ba130992092125ab365cd5fff0..22af9f370f82c8fd74fcf9c40bf018d79ff901d2 100644
--- a/content/shell/test_runner/web_test_delegate.h
+++ b/content/shell/test_runner/web_test_delegate.h
@@ -70,6 +70,9 @@ class WebTestDelegate {
   virtual void SetDeviceOrientationData(
       const blink::WebDeviceOrientationData& data) = 0;
 
+  // Add a message to stderr.

[Rick Byers, 2017/03/09 13:22:24]

nit: explicitly add "(not saved to expected output files, for debugging only)"
to make the purpose clear.

[Dan Elphick, 2017/03/09 13:41:40]

Done.

+  virtual void PrintLogMessage(const std::string& message) = 0;
+
   // Add a message to the text dump for the layout test.
   virtual void PrintMessage(const std::string& message) = 0;