Add CHECKs to investigate ServiceWorkerControlleeRequestHandler crash.

content/browser/service_worker/service_worker_controllee_request_handler.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_controllee_request_handler.h"
 
 #include <memory>
 #include <set>
 #include <string>
 
@@ skipping 386 matching lines @@
     return;
   }
   version->RegisterStatusChangeCallback(
       base::Bind(&self::OnUpdatedVersionStatusChanged,
                  weak_factory_.GetWeakPtr(), registration, version));
 }
 
 void ServiceWorkerControlleeRequestHandler::PrepareForSubResource() {
   DCHECK(job_.get());
   DCHECK(context_);
-  DCHECK(provider_host_->active_version());
+
+  if (!provider_host_->active_version()) {
+    // TODO(falken): For debugging. Remove once https://crbug.com/655910 is
+    // resolved.
+    CHECK(provider_host_->controller_was_deleted());
+  }
+
   MaybeForwardToServiceWorker(job_.get(), provider_host_->active_version());
 }
 
 void ServiceWorkerControlleeRequestHandler::OnPrepareToRestart() {
   use_network_ = true;
   ClearJob();
 }
 
 ServiceWorkerVersion*
 ServiceWorkerControlleeRequestHandler::GetServiceWorkerVersion(
@@ skipping 16 matching lines @@
   if (!provider_host_) {
     *result = ServiceWorkerMetrics::REQUEST_JOB_ERROR_NO_PROVIDER_HOST;
     return false;
   }
   return true;
 }
 
 void ServiceWorkerControlleeRequestHandler::MainResourceLoadFailed() {
   DCHECK(provider_host_);
   // Detach the controller so subresource requests also skip the worker.
-  provider_host_->NotifyControllerLost();
+  provider_host_->NotifyControllerLost(false /* was_deleted */);
 }
 
 void ServiceWorkerControlleeRequestHandler::ClearJob() {
   job_.reset();
 }
 
 }  // namespace content