Extract ResultCatcher from ExtensionApiTest. Use it in ShellApiTest.

extensions/shell/test/shell_test.cc

Index: extensions/shell/test/shell_test.cc
diff --git a/extensions/shell/test/shell_test.cc b/extensions/shell/test/shell_test.cc
index e67400db97e5eb0a0dab8520c5ac9bc13624b7ef..294fbaa898705f61c59d047e34d517343f4ef1b2 100644
--- a/extensions/shell/test/shell_test.cc
+++ b/extensions/shell/test/shell_test.cc
@@ -5,7 +5,6 @@
 #include "extensions/shell/test/shell_test.h"
 
 #include "base/command_line.h"
-#include "base/files/file_path.h"
 #include "base/logging.h"
 #include "content/public/common/content_switches.h"
 #include "extensions/browser/extension_system.h"
@@ -47,11 +46,4 @@ void AppShellTest::RunTestOnMainThreadLoop() {
   ShellDesktopController::instance()->CloseAppWindows();
 }
 
-bool AppShellTest::LoadAndLaunchApp(const base::FilePath& app_dir) {
-  bool loaded = extension_system_->LoadApp(app_dir);
-  if (loaded)
-    extension_system_->LaunchApp();
-  return loaded;
-}
-
 }  // namespace extensions