[ChromeDriver] Subscribe PerformanceLogger to CommandListener interface

chrome/test/chromedriver/session.h

Index: chrome/test/chromedriver/session.h
diff --git a/chrome/test/chromedriver/session.h b/chrome/test/chromedriver/session.h
index fe837fbf061d252393742ef161326ad3cf8051fe..2df16d7ae6912c4ae08824f94ada9edd25cb9885 100644
--- a/chrome/test/chromedriver/session.h
+++ b/chrome/test/chromedriver/session.h
@@ -16,6 +16,7 @@
 #include "chrome/test/chromedriver/basic_types.h"
 #include "chrome/test/chromedriver/chrome/device_metrics.h"
 #include "chrome/test/chromedriver/chrome/geoposition.h"
+#include "chrome/test/chromedriver/command_listener.h"
 
 namespace base {
 class DictionaryValue;
@@ -77,6 +78,11 @@ struct Session {
   base::ScopedTempDir temp_dir;
   scoped_ptr<base::DictionaryValue> capabilities;
   bool auto_reporting_enabled;
+  // |command_listeners| should be declared after |chrome|. When the |Session|
+  // is destroyed, |command_listeners| should be freed first, since some
+  // |CommandListener|s might be |CommandListenerProxy|s that forward to
+  // |DevToolsEventListener|s owned by |chrome|.
+  ScopedVector<CommandListener> command_listeners;
 };
 
 Session* GetThreadLocalSession();