Send screenshots back to the client for debugging

chrome/test/webdriver/commands/create_session.cc

Index: chrome/test/webdriver/commands/create_session.cc
diff --git a/chrome/test/webdriver/commands/create_session.cc b/chrome/test/webdriver/commands/create_session.cc
index b23158e02b18cc88c7d60e395ef09dbd92a235b7..302da385bf20eb2fdf7584c222b037b16a5f3bbc 100644
--- a/chrome/test/webdriver/commands/create_session.cc
+++ b/chrome/test/webdriver/commands/create_session.cc
@@ -37,6 +37,13 @@ void CreateSession::ExecutePost(Response* const response) {
     return;
   }
 
+  bool screenshot_on_error = false;
+  DictionaryValue* capabilities = NULL;
+  if (GetDictionaryParameter("desiredCapabilities", &capabilities)) {
+    capabilities->GetBoolean("takeScreenshotOnError", &screenshot_on_error);
+    session->set_screenshot_on_error(screenshot_on_error);
+  }
+
   VLOG(1) << "Created session " << session->id();
   std::ostringstream stream;
   stream << "http://" << session_manager->GetAddress() << "/session/"