Split ExtensionTestObserver and move to //extensions.

chrome/browser/chromeos/first_run/drive_first_run_browsertest.cc

Index: chrome/browser/chromeos/first_run/drive_first_run_browsertest.cc
diff --git a/chrome/browser/chromeos/first_run/drive_first_run_browsertest.cc b/chrome/browser/chromeos/first_run/drive_first_run_browsertest.cc
index 5e3ed08554dffcefe303fc68ce66c1483c4292fd..0eba17ed8a989eb53e0e54a1dddfdccd7efc0b2f 100644
--- a/chrome/browser/chromeos/first_run/drive_first_run_browsertest.cc
+++ b/chrome/browser/chromeos/first_run/drive_first_run_browsertest.cc
@@ -11,8 +11,9 @@
 #include "base/strings/string_number_conversions.h"
 #include "chrome/browser/chromeos/first_run/drive_first_run_controller.h"
 #include "chrome/browser/extensions/crx_installer.h"
+#include "chrome/browser/extensions/extension_browser_test_notification_observer.h"
 #include "chrome/browser/extensions/extension_service.h"
-#include "chrome/browser/extensions/extension_test_notification_observer.h"
+#include "chrome/browser/ui/browser.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "content/public/test/test_utils.h"
@@ -128,7 +129,7 @@ void DriveFirstRunTest::InstallApp() {
       extensions::CrxInstaller::CreateSilent(extension_service);
 
   installer->InstallCrx(test_data_dir_.AppendASCII(kTestAppCrxName));
-  ExtensionTestNotificationObserver observer(browser());
+  ExtensionBrowserTestNotificationObserver observer(browser());
   observer.WaitForExtensionLoad();
 
   ASSERT_TRUE(extension_service->GetExtensionById(kTestAppId, false));