[proof-of-concept] SW thread independent of the main thread

chrome/browser/push_messaging/push_messaging_service_impl.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 "chrome/browser/push_messaging/push_messaging_service_impl.h"
 
 #include <vector>
 
 #include "base/barrier_closure.h"
 #include "base/base64url.h"
@@ skipping 556 matching lines @@
 // GetEncryptionInfo methods ---------------------------------------------------
 
 void PushMessagingServiceImpl::GetEncryptionInfo(
     const GURL& origin,
     int64_t service_worker_registration_id,
     const PushMessagingService::EncryptionInfoCallback& callback) {
   PushMessagingAppIdentifier app_identifier =
       PushMessagingAppIdentifier::FindByServiceWorker(
           profile_, origin, service_worker_registration_id);
 
-  DCHECK(!app_identifier.is_null());
-
+  // DCHECK(!app_identifier.is_null());
+  if (app_identifier.is_null())
+    return;
   GetGCMDriver()->GetEncryptionInfo(
       app_identifier.app_id(),
       base::Bind(&PushMessagingServiceImpl::DidGetEncryptionInfo,
                  weak_factory_.GetWeakPtr(), callback));
 }
 
 void PushMessagingServiceImpl::DidGetEncryptionInfo(
     const PushMessagingService::EncryptionInfoCallback& callback,
     const std::string& p256dh,
     const std::string& auth_secret) const {
@@ skipping 210 matching lines @@
          blink::WebPushPermissionStatusGranted;
 }
 
 gcm::GCMDriver* PushMessagingServiceImpl::GetGCMDriver() const {
   gcm::GCMProfileService* gcm_profile_service =
       gcm::GCMProfileServiceFactory::GetForProfile(profile_);
   CHECK(gcm_profile_service);
   CHECK(gcm_profile_service->driver());
   return gcm_profile_service->driver();
 }