Fix crash when user closes window prior to the "Confirm Install" prompt showing

chrome/browser/ui/cocoa/extensions/windowed_install_dialog_controller_browsertest.mm

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "chrome/browser/ui/cocoa/extensions/windowed_install_dialog_controller.h"
 
 #include "base/run_loop.h"
 #include "base/threading/sequenced_worker_pool.h"
 #include "chrome/browser/ui/browser.h"
 #import "chrome/browser/ui/cocoa/extensions/extension_install_prompt_test_utils.h"
 #import "chrome/browser/ui/cocoa/extensions/extension_install_view_controller.h"
 #include "chrome/test/base/in_process_browser_test.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/test/test_utils.h"
 #include "extensions/common/extension.h"
 
 namespace {
 
 // Similar to ShowExtensionInstallDialogImpl except this allows the created
 // dialog controller to be captured and manipulated for tests.
 void TestingShowAppListInstallDialogController(
     WindowedInstallDialogController** controller,
-    const ExtensionInstallPrompt::ShowParams& show_params,
+    ExtensionInstallPromptShowParams* show_params,
     ExtensionInstallPrompt::Delegate* delegate,
     scoped_refptr<ExtensionInstallPrompt::Prompt> prompt) {
   *controller =
       new WindowedInstallDialogController(show_params, delegate, prompt);
 }
 
 typedef InProcessBrowserTest WindowedInstallDialogControllerBrowserTest;
 
 }  // namespace
 
@@ skipping 25 matching lines @@
   EXPECT_EQ(0, delegate.abort_count());
 
   // Press cancel to close the window.
   [[controller->GetViewController() cancelButton] performClick:nil];
   EXPECT_FALSE([window delegate]);
   EXPECT_EQ(1, delegate.abort_count());
 
   // Ensure the window is closed.
   EXPECT_FALSE([window isVisible]);
 }