Add a flag that lets the webstore show a different UI on app install.

chrome/browser/extensions/crx_installer.h

 // Copyright (c) 2011 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_CRX_INSTALLER_H_
 #define CHROME_BROWSER_EXTENSIONS_CRX_INSTALLER_H_
 #pragma once
 
 #include <string>
 
@@ skipping 43 matching lines @@
   // prompt. This should only be called on the UI thread.
   // crbug.com/54916
   static void SetWhitelistedInstallId(const std::string& id);
 
   struct WhitelistEntry {
     WhitelistEntry();
     ~WhitelistEntry();
 
     scoped_ptr<base::DictionaryValue> parsed_manifest;
     std::string localized_name;
+
+    // Whether to use a bubble notification when an app is installed, instead of
+    // the default behavior of transitioning to the new tab page.
+    bool use_app_installed_bubble;
   };
 
   // Exempt the next extension install with |id| from displaying a confirmation
   // prompt, since the user already agreed to the install via
   // beginInstallWithManifest. We require that the extension manifest matches
   // the manifest in |entry|, which is what was used to prompt with. Ownership
   // of |entry| is transferred here.
   static void SetWhitelistEntry(const std::string& id, WhitelistEntry* entry);
 
   // Returns the previously stored manifest from a call to SetWhitelistEntry.
@@ skipping 205 matching lines @@
   std::string original_mime_type_;
 
   // What caused this install?  Used only for histograms that report
   // on failure rates, broken down by the cause of the install.
   extension_misc::CrxInstallCause install_cause_;
 
   DISALLOW_COPY_AND_ASSIGN(CrxInstaller);
 };
 
 #endif  // CHROME_BROWSER_EXTENSIONS_CRX_INSTALLER_H_