Add a context_ null check needed in case of DeleteAndStartOver.

content/browser/service_worker/service_worker_script_cache_map.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_script_cache_map.h"
 
 #include "base/logging.h"
 #include "content/browser/service_worker/service_worker_context_core.h"
 #include "content/browser/service_worker/service_worker_storage.h"
 #include "content/browser/service_worker/service_worker_version.h"
@@ skipping 23 matching lines @@
   if (found == resource_map_.end())
     return kInvalidServiceWorkerResponseId;
   return found->second.size_bytes;
 }
 
 void ServiceWorkerScriptCacheMap::NotifyStartedCaching(
     const GURL& url, int64 resource_id) {
   DCHECK_EQ(kInvalidServiceWorkerResponseId, LookupResourceId(url));
   DCHECK(owner_->status() == ServiceWorkerVersion::NEW ||
          owner_->status() == ServiceWorkerVersion::INSTALLING);
+  if (!context_)
+    return;  // Our storage has been wiped via DeleteAndStartOver.
   resource_map_[url] =
       ServiceWorkerDatabase::ResourceRecord(resource_id, url, -1);
   context_->storage()->StoreUncommittedResponseId(resource_id);
 }
 
 void ServiceWorkerScriptCacheMap::NotifyFinishedCaching(
     const GURL& url,
     int64 size_bytes,
     const net::URLRequestStatus& status) {
   DCHECK_NE(kInvalidServiceWorkerResponseId, LookupResourceId(url));
   DCHECK(owner_->status() == ServiceWorkerVersion::NEW ||
          owner_->status() == ServiceWorkerVersion::INSTALLING);
+  if (!context_)
+    return;  // Our storage has been wiped via DeleteAndStartOver.
   if (!status.is_success()) {
     context_->storage()->DoomUncommittedResponse(LookupResourceId(url));
     resource_map_.erase(url);
     if (owner_->script_url() == url)
       main_script_status_ = status;
   } else {
     resource_map_[url].size_bytes = size_bytes;
   }
 }
 
@@ skipping 11 matching lines @@
     const std::vector<ServiceWorkerDatabase::ResourceRecord>& resources) {
   DCHECK(resource_map_.empty());
   typedef std::vector<ServiceWorkerDatabase::ResourceRecord> RecordVector;
   for (RecordVector::const_iterator it = resources.begin();
        it != resources.end(); ++it) {
     resource_map_[it->url] = *it;
   }
 }
 
 }  // namespace content