Always destroy CrxInstaller on the UI Thread

chrome/browser/extensions/crx_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/crx_installer.h"
 
 #include <map>
 #include <set>
 
 #include "base/bind.h"
@@ skipping 145 matching lines @@
   if (approval->minimum_version.get()) {
     expected_version_.reset(new Version(*approval->minimum_version));
     expected_version_strict_checking_ = false;
   }
 
   show_dialog_callback_ = approval->show_dialog_callback;
   set_is_ephemeral(approval->is_ephemeral);
 }
 
 CrxInstaller::~CrxInstaller() {
-  // Make sure the UI is deleted on the ui thread.
-  if (client_) {
-    BrowserThread::DeleteSoon(BrowserThread::UI, FROM_HERE, client_);
-    client_ = NULL;
-  }
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  // Ensure |client_| and |install_checker_| data members are destroyed on the
+  // UI thread. The |client_| dialog has a weak reference as |this| is its
+  // delegate, and |install_checker_| owns WeakPtrs, so must be destroyed on the
+  // same thread that created it.
 }
 
 void CrxInstaller::InstallCrx(const base::FilePath& source_file) {
   InstallCrxFile(CRXFileInfo(source_file));
 }
 
 void CrxInstaller::InstallCrxFile(const CRXFileInfo& source_file) {
   ExtensionService* service = service_weak_.get();
   if (!service || service->browser_terminating())
     return;
@@ skipping 727 matching lines @@
   if (!prefs->DidExtensionEscalatePermissions(extension()->id()))
     return;
 
   if (client_) {
     AddRef();  // Balanced in InstallUIProceed() and InstallUIAbort().
     client_->ConfirmReEnable(this, extension());
   }
 }
 
 }  // namespace extensions