Fix race condition in content_shell which could lead to an assert on shutdown with PlzNavigate.

content/shell/browser/shell_browser_context.cc

 // Copyright 2013 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 "content/shell/browser/shell_browser_context.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 49 matching lines @@
       net_log_(net_log),
       guest_manager_(NULL) {
   InitWhileIOAllowed();
   BrowserContextDependencyManager::GetInstance()->
       CreateBrowserContextServices(this);
 }
 
 ShellBrowserContext::~ShellBrowserContext() {
   BrowserContextDependencyManager::GetInstance()->
       DestroyBrowserContextServices(this);
-  ShutdownStoragePartitions();
+  // Need to destruct the ResourceContext before posting tasks which may delete
+  // the URLRequestContext because ResourceContext's destructor will remove any
+  // outstanding request while URLRequestContext's destructor ensures that there
+  // are no more outstanding requests.
   if (resource_context_) {
     BrowserThread::DeleteSoon(
       BrowserThread::IO, FROM_HERE, resource_context_.release());
   }
+  ShutdownStoragePartitions();
 }
 
 void ShellBrowserContext::InitWhileIOAllowed() {
   base::CommandLine* cmd_line = base::CommandLine::ForCurrentProcess();
   if (cmd_line->HasSwitch(switches::kIgnoreCertificateErrors))
     ignore_certificate_errors_ = true;
   if (cmd_line->HasSwitch(switches::kContentShellDataPath)) {
     path_ = cmd_line->GetSwitchValuePath(switches::kContentShellDataPath);
     if (base::DirectoryExists(path_) || base::CreateDirectory(path_))  {
       // BrowserContext needs an absolute path, which we would normally get via
@@ skipping 126 matching lines @@
   return permission_manager_.get();
 }
 
 BackgroundSyncController* ShellBrowserContext::GetBackgroundSyncController() {
   if (!background_sync_controller_)
     background_sync_controller_.reset(new MockBackgroundSyncController());
   return background_sync_controller_.get();
 }
 
 }  // namespace content