Add default testing command line flags in UITestBase instead of ProxyLauncher.

chrome/test/webdriver/webdriver_server.cc

Index: chrome/test/webdriver/webdriver_server.cc
diff --git a/chrome/test/webdriver/webdriver_server.cc b/chrome/test/webdriver/webdriver_server.cc
index a9a1bb20f1fa70494c8861ea3d5e8a7fc2124110..899ed284c5abcaea63d907c16fddeda356abeb1d 100644
--- a/chrome/test/webdriver/webdriver_server.cc
+++ b/chrome/test/webdriver/webdriver_server.cc
@@ -305,13 +305,15 @@ int RunChromeDriver() {
 
   // The tests depend on parsing the first line ChromeDriver outputs,
   // so all other logging should happen after this.
-  std::cout << "Started ChromeDriver" << std::endl
-            << "port=" << port << std::endl
-            << "version=" << chrome::kChromeVersion << std::endl;
-  if (logging_success)
-    std::cout << "log=" << FileLog::Get()->path().value() << std::endl;
-  else
-    std::cout << "Log file could not be created" << std::endl;
+  if (!cmd_line->HasSwitch("silent")) {
+    std::cout << "Started ChromeDriver" << std::endl
+              << "port=" << port << std::endl
+              << "version=" << chrome::kChromeVersion << std::endl;
+    if (logging_success)
+      std::cout << "log=" << FileLog::Get()->path().value() << std::endl;
+    else
+      std::cout << "Log file could not be created" << std::endl;
+  }
 
   // Run until we receive command to shutdown.
   // Don't call mg_stop because mongoose will hang if clients are still