Support for interactive set-chrome-as-default in Windows.

chrome/browser/first_run/first_run.cc

 // Copyright (c) 2012 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/first_run/first_run.h"
 
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
 #include "base/file_util.h"
 #include "base/metrics/histogram.h"
@@ skipping 357 matching lines @@
 
   // Launch the first run dialog only for certain builds, and only if the user
   // has not already set preferences.
   if (IsOrganicFirstRun() && !local_state_file_exists) {
     // The home page string may be set in the preferences, but the user should
     // initially use Chrome with the NTP as home page in organic builds.
     profile->GetPrefs()->SetBoolean(prefs::kHomePageIsNewTabPage, true);
     ShowFirstRunDialog(profile);
   }
 
-  if (make_chrome_default)
+  if (make_chrome_default &&
+      ShellIntegration::CanSetAsDefaultBrowser() ==
+          ShellIntegration::CHANGE_DEFAULT_UNATTENDED) {
     ShellIntegration::SetAsDefaultBrowser();
+  }
 
   // Display the first run bubble if there is a default search provider.
   TemplateURLService* template_url =
       TemplateURLServiceFactory::GetForProfile(profile);
   if (template_url && template_url->GetDefaultSearchProvider())
     FirstRunBubbleLauncher::ShowFirstRunBubbleSoon();
   SetShowWelcomePagePref();
   SetPersonalDataManagerFirstRunPref();
 }
 #endif  // !defined(USE_AURA)
@@ skipping 143 matching lines @@
 
   // Reset the preference and notifications to avoid showing the bubble again.
   prefs->SetBoolean(prefs::kShouldShowFirstRunBubble, false);
 
   // Show the bubble now and destroy this bubble launcher.
   browser->ShowFirstRunBubble();
   delete this;
 }
 
 }  // namespace first_run