Debug crash in WebstoreInstaller::StartDownload()

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 "base/basictypes.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/file_util.h"
@@ skipping 154 matching lines @@
                                      const std::string& id,
                                      scoped_ptr<Approval> approval,
                                      int flags)
     : profile_(profile),
       delegate_(delegate),
       controller_(controller),
       id_(id),
       download_item_(NULL),
       flags_(flags),
       approval_(approval.release()) {
+  // TODO(benjhayden): Change this CHECK to DCHECK after http://crbug.com/126013
+  CHECK(controller_);
   download_url_ = GetWebstoreInstallURL(id, flags & FLAG_INLINE_INSTALL ?
       kInlineInstallSource : kDefaultInstallSource);
 
   registrar_.Add(this, chrome::NOTIFICATION_CRX_INSTALLER_DONE,
                  content::NotificationService::AllSources());
   registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_INSTALLED,
                  content::Source<Profile>(profile->GetOriginalProfile()));
   registrar_.Add(this, chrome::NOTIFICATION_EXTENSION_INSTALL_ERROR,
                  content::Source<CrxInstaller>(NULL));
 }
 
 void WebstoreInstaller::Start() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   AddRef();  // Balanced in ReportSuccess and ReportFailure.
 
   if (!Extension::IdIsValid(id_)) {
     ReportFailure(kInvalidIdError);
     return;
   }
 
   FilePath download_path = DownloadPrefs::FromDownloadManager(
       BrowserContext::GetDownloadManager(profile_))->download_path();
   BrowserThread::PostTask(
       BrowserThread::FILE, FROM_HERE,
       base::Bind(&GetDownloadFilePath, download_path, id_,
-                 base::Bind(&WebstoreInstaller::StartDownload,
-                            base::Unretained(this))));
-
+                 base::Bind(&WebstoreInstaller::StartDownload, this)));
 }
 
 void WebstoreInstaller::Observe(int type,
                                 const content::NotificationSource& source,
                                 const content::NotificationDetails& details) {
   switch (type) {
     case chrome::NOTIFICATION_CRX_INSTALLER_DONE: {
       const Extension* extension =
           content::Details<const Extension>(details).ptr();
       CrxInstaller* installer = content::Source<CrxInstaller>(source).ptr();
@@ skipping 86 matching lines @@
   }
 }
 
 void WebstoreInstaller::OnDownloadOpened(DownloadItem* download) {
   CHECK_EQ(download_item_, download);
 }
 
 void WebstoreInstaller::StartDownload(const FilePath& file) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
-  if (file.empty()) {
+  if (file.empty() || !controller_->GetWebContents()) {
     ReportFailure(kDownloadDirectoryError);
     return;
   }
 
   content::DownloadSaveInfo save_info;
   save_info.file_path = file;
 
   // The download url for the given extension is contained in |download_url_|.
   // We will navigate the current tab to this url to start the download. The
   // download system will then pass the crx to the CrxInstaller.
   download_util::RecordDownloadSource(
       download_util::INITIATED_BY_WEBSTORE_INSTALLER);
   scoped_ptr<DownloadUrlParameters> params(
       DownloadUrlParameters::FromWebContents(
           controller_->GetWebContents(), download_url_, save_info));
-  params->set_referrer(
-      content::Referrer(controller_->GetActiveEntry()->GetURL(),
-                        WebKit::WebReferrerPolicyDefault));
+  if (controller_->GetActiveEntry())
+    params->set_referrer(
+        content::Referrer(controller_->GetActiveEntry()->GetURL(),
+                          WebKit::WebReferrerPolicyDefault));
   params->set_callback(base::Bind(&WebstoreInstaller::OnDownloadStarted, this));
   BrowserContext::GetDownloadManager(profile_)->DownloadUrl(params.Pass());
 }
 
 void WebstoreInstaller::ReportFailure(const std::string& error) {
   if (delegate_) {
     delegate_->OnExtensionInstallFailure(id_, error);
     delegate_ = NULL;
   }
 
   Release();  // Balanced in Start().
 }
 
 void WebstoreInstaller::ReportSuccess() {
   if (delegate_) {
     delegate_->OnExtensionInstallSuccess(id_);
     delegate_ = NULL;
   }
 
   Release();  // Balanced in Start().
 }