Use BookmarkAppConfirmationView on Mac. Delete the NSAlert Mac uses currently.

chrome/browser/extensions/bookmark_app_helper.h

Index: chrome/browser/extensions/bookmark_app_helper.h
diff --git a/chrome/browser/extensions/bookmark_app_helper.h b/chrome/browser/extensions/bookmark_app_helper.h
index 174ede8d9a4891287e26b2ad327c2fde0ba8adc4..fdefc91618129fbb4700e3a4d8d853f98b3f47ca 100644
--- a/chrome/browser/extensions/bookmark_app_helper.h
+++ b/chrome/browser/extensions/bookmark_app_helper.h
@@ -32,6 +32,10 @@ namespace extensions {
 class CrxInstaller;
 class Extension;
 
+namespace test {
+class TestBookmarkAppHelper;
+}
+
 // A helper class for creating bookmark apps from a WebContents.
 class BookmarkAppHelper : public content::NotificationObserver {
  public:
@@ -110,7 +114,7 @@ class BookmarkAppHelper : public content::NotificationObserver {
                            const content::Manifest& manifest);
 
  private:
-  friend class TestBookmarkAppHelper;
+  friend class test::TestBookmarkAppHelper;
 
   // Called by the WebContents when the manifest has been downloaded. If there
   // is no manifest, or the WebContents is destroyed before the manifest could
@@ -119,8 +123,9 @@ class BookmarkAppHelper : public content::NotificationObserver {
                         const content::Manifest& manifest);
 
   // Performs post icon download tasks including installing the bookmark app.
-  void OnIconsDownloaded(bool success,
-                         const std::map<GURL, std::vector<SkBitmap> >& bitmaps);
+  virtual void OnIconsDownloaded(
+      bool success,
+      const std::map<GURL, std::vector<SkBitmap>>& bitmaps);
 
   // Called after the bubble has been shown, and the user has either accepted or
   // the dialog was dismissed.