Don't install external extensions in tests

chrome/browser/extensions/default_apps.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/extensions/default_apps.h"
 
 #include "base/command_line.h"
 #include "chrome/browser/browser_process.h"
 #if !defined(OS_ANDROID)
 #include "chrome/browser/first_run/first_run.h"
@@ skipping 96 matching lines @@
     case kNeverInstallDefaultApps:
       install_apps = false;
       break;
     default:
       NOTREACHED();
   }
 
   if (install_apps && !IsLocaleSupported())
     install_apps = false;
 
-  if (CommandLine::ForCurrentProcess()->HasSwitch(
-      switches::kDisableDefaultApps)) {
-    install_apps = false;
-  }
-
   // Default apps are only installed on profile creation or a new chrome
   // download.
   if (state == kUnknown) {
     if (install_apps) {
       profile_->GetPrefs()->SetInteger(prefs::kDefaultAppsInstallState,
                                        kAlreadyInstalledDefaultApps);
     } else {
       profile_->GetPrefs()->SetInteger(prefs::kDefaultAppsInstallState,
                                        kNeverInstallDefaultApps);
     }
@@ skipping 39 matching lines @@
     for (std::set<std::string>::iterator it = new_default_apps.begin();
          it != new_default_apps.end(); ++it) {
       prefs->Remove(*it, NULL);
     }
   }
 
   ExternalProviderImpl::SetPrefs(prefs);
 }
 
 }  // namespace default_apps