ServiceWorker: Fix crash during shutdown in single-process mode

content/browser/service_worker/service_worker_process_manager.cc

 // Copyright 2014 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/browser/service_worker/service_worker_process_manager.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <utility>
@@ skipping 59 matching lines @@
   CHECK(instance_info_.empty());
 }
 
 void ServiceWorkerProcessManager::Shutdown() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
   {
     base::AutoLock lock(browser_context_lock_);
     browser_context_ = nullptr;
   }
 
-  for (std::map<int, ProcessInfo>::const_iterator it = instance_info_.begin();
-       it != instance_info_.end();
-       ++it) {
-    RenderProcessHost::FromID(it->second.process_id)
-        ->DecrementServiceWorkerRefCount();
+  if (!RenderProcessHost::run_renderer_in_process()) {

[nhiroki, 2017/04/17 23:26:21]

Could you add a comment about why we need to skip this in the single process
mode like the 1st paragraph on the CL description?

+    for (std::map<int, ProcessInfo>::const_iterator it = instance_info_.begin();
+         it != instance_info_.end(); ++it) {
+      RenderProcessHost::FromID(it->second.process_id)
+          ->DecrementServiceWorkerRefCount();
+    }
   }
   instance_info_.clear();
 }
 
 bool ServiceWorkerProcessManager::IsShutdown() {
   base::AutoLock lock(browser_context_lock_);
   return !browser_context_;
 }
 
 void ServiceWorkerProcessManager::AddProcessReferenceToPattern(
@@ skipping 239 matching lines @@
 namespace std {
 // Destroying ServiceWorkerProcessManagers only on the UI thread allows the
 // member WeakPtr to safely guard the object's lifetime when used on that
 // thread.
 void default_delete<content::ServiceWorkerProcessManager>::operator()(
     content::ServiceWorkerProcessManager* ptr) const {
   content::BrowserThread::DeleteSoon(
       content::BrowserThread::UI, FROM_HERE, ptr);
 }
 }  // namespace std