Prevent browser crashes when a site is added to shelf with extensions blacklisted.

chrome/browser/extensions/bookmark_app_helper.cc

 // Copyright 2014 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.
 
 #include "chrome/browser/extensions/bookmark_app_helper.h"
 
 #include <cctype>
 
 #include "base/prefs/pref_service.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 713 matching lines @@
     web_app::RevealAppShimInFinderForApp(current_profile, extension);
   }
 #endif
 
   callback_.Run(extension, web_app_info_);
 }
 
 void BookmarkAppHelper::Observe(int type,
                                 const content::NotificationSource& source,
                                 const content::NotificationDetails& details) {
+  // TODO(dominickn): bookmark app creation fails when extensions cannot be
+  // created (e.g. due to management policies). Add to shelf visibility should
+  // be gated on whether extensions can be created - see crbug.com/545541.
   switch (type) {
     case extensions::NOTIFICATION_CRX_INSTALLER_DONE: {
       const Extension* extension =
           content::Details<const Extension>(details).ptr();
-      DCHECK(extension);
-      DCHECK_EQ(AppLaunchInfo::GetLaunchWebURL(extension),
-                web_app_info_.app_url);
-      FinishInstallation(extension);
+      if (extension) {
+        DCHECK_EQ(AppLaunchInfo::GetLaunchWebURL(extension),
+                  web_app_info_.app_url);
+        FinishInstallation(extension);
+      } else {
+        callback_.Run(nullptr, web_app_info_);
+      }
       break;
     }
     case extensions::NOTIFICATION_EXTENSION_INSTALL_ERROR:
       callback_.Run(nullptr, web_app_info_);
       break;
     default:
       NOTREACHED();
       break;
   }
 }
@@ skipping 38 matching lines @@
       extension, info_list, base::Bind(&OnIconsLoaded, web_app_info, callback));
 }
 
 bool IsValidBookmarkAppUrl(const GURL& url) {
   URLPattern origin_only_pattern(Extension::kValidBookmarkAppSchemes);
   origin_only_pattern.SetMatchAllURLs(true);
   return url.is_valid() && origin_only_pattern.MatchesURL(url);
 }
 
 }  // namespace extensions