Extract InstallVerifier from ExtensionSystem.

chrome/browser/extensions/webstore_installer.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/webstore_installer.h"
 
 #include <set>
 #include <vector>
 
 #include "base/basictypes.h"
@@ skipping 310 matching lines @@
   info.extension_id = id_;
   pending_modules_.push_back(info);
 
   total_modules_ = pending_modules_.size();
 
   std::set<std::string> ids;
   std::list<SharedModuleInfo::ImportInfo>::const_iterator i;
   for (i = pending_modules_.begin(); i != pending_modules_.end(); ++i) {
     ids.insert(i->extension_id);
   }
-  ExtensionSystem::Get(profile_)->install_verifier()->AddProvisional(ids);
+  InstallVerifier::Get(profile_)->AddProvisional(ids);
 
   std::string name;
   if (!approval_->manifest->value()->GetString(manifest_keys::kName, &name)) {
     NOTREACHED();
   }
   extensions::InstallTracker* tracker =
       extensions::InstallTrackerFactory::GetForBrowserContext(profile_);
   extensions::InstallObserver::ExtensionInstallParams params(
       id_,
       name,
@@ skipping 424 matching lines @@
         1,
         kMaxSizeKb,
         kNumBuckets);
   }
   UMA_HISTOGRAM_BOOLEAN(
       "Extensions.WebstoreDownload.InterruptTotalSizeUnknown",
       total_bytes <= 0);
 }
 
 }  // namespace extensions