Add webdriver endpoint to send custom debugger commands

chrome/test/chromedriver/capabilities.h

Index: chrome/test/chromedriver/capabilities.h
diff --git a/chrome/test/chromedriver/capabilities.h b/chrome/test/chromedriver/capabilities.h
index a438064a3c06336fb25edfa08ad64d40fdb0c248..068c5a19daed17b2b1439fcb4accdda9a63faa0d 100644
--- a/chrome/test/chromedriver/capabilities.h
+++ b/chrome/test/chromedriver/capabilities.h
@@ -24,6 +24,7 @@
 namespace base {
 class CommandLine;
 class DictionaryValue;
+class ListValue;
 }
 
 class Status;
@@ -150,6 +151,8 @@ struct Capabilities {
 
   PerfLoggingPrefs perf_logging_prefs;
 
+  std::unique_ptr<base::ListValue> devtools_events_logging_prefs;
+
   std::unique_ptr<base::DictionaryValue> prefs;
 
   Switches switches;