Let pyauto create an attached webdriver instance to manipulate web pages.

chrome/test/ui/ui_test.cc

Index: chrome/test/ui/ui_test.cc
diff --git a/chrome/test/ui/ui_test.cc b/chrome/test/ui/ui_test.cc
index d02eb70081835ffa46ea635e705584fb254acba4..81f03eba984413036a6ed70dc8240bb9ff62388d 100644
--- a/chrome/test/ui/ui_test.cc
+++ b/chrome/test/ui/ui_test.cc
@@ -125,8 +125,8 @@ void UITestBase::SetUp() {
   test_start_time_ = Time::NowFromSystemTime();
 
   SetLaunchSwitches();
-  launcher_->InitializeConnection(DefaultLaunchState(),
-                                  wait_for_initial_loads_);
+  ASSERT_TRUE(launcher_->InitializeConnection(DefaultLaunchState(),
+                                              wait_for_initial_loads_));
 }
 
 void UITestBase::TearDown() {