Add CHECKs to investigate ServiceWorkerControlleeRequestHandler crash.

If the crash still occurs and the CHECKs pass, we know the null
active version is due to SWRegistration::DeleteVersion.

BUG=655910

Review-Url: https://codereview.chromium.org/2570453002
Cr-Commit-Position: refs/heads/master@{#437830}

content/browser/service_worker/service_worker_controllee_request_handler.cc

@@ -404,7 +404,13 @@ void ServiceWorkerControlleeRequestHandler::OnUpdatedVersionStatusChanged(
 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());
 }
 
@@ -441,7 +447,7 @@ bool ServiceWorkerControlleeRequestHandler::RequestStillValid(
 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() {

content/browser/service_worker/service_worker_provider_host.cc

@@ -116,7 +116,8 @@ ServiceWorkerProviderHost::ServiceWorkerProviderHost(
       parent_frame_security_level_(parent_frame_security_level),
       context_(context),
       dispatcher_host_(dispatcher_host),
-      allow_association_(true) {
+      allow_association_(true),
+      controller_was_deleted_(false) {
   DCHECK_NE(SERVICE_WORKER_PROVIDER_UNKNOWN, provider_type_);
 
   // PlzNavigate
@@ -208,6 +209,9 @@ void ServiceWorkerProviderHost::OnSkippedWaiting(
   if (!controlling_version_)
     return;
   ServiceWorkerVersion* active_version = registration->active_version();
+  // TODO(falken): Change to DCHECK once https://crbug.com/655910 is
+  // resolved.
+  CHECK(active_version);
   DCHECK_EQ(active_version->status(), ServiceWorkerVersion::ACTIVATING);
   SetControllerVersionAttribute(active_version,
                                 true /* notify_controllerchange */);
@@ -354,7 +358,9 @@ ServiceWorkerProviderHost::MatchRegistration() const {
   return nullptr;
 }
 
-void ServiceWorkerProviderHost::NotifyControllerLost() {
+void ServiceWorkerProviderHost::NotifyControllerLost(bool was_deleted) {
+  if (was_deleted)
+    controller_was_deleted_ = true;
   SetControllerVersionAttribute(nullptr, true /* notify_controllerchange */);
 }
 
@@ -450,7 +456,8 @@ void ServiceWorkerProviderHost::AddScopedProcessReferenceToPattern(
 
 void ServiceWorkerProviderHost::ClaimedByRegistration(
     ServiceWorkerRegistration* registration) {
-  DCHECK(registration->active_version());
+  // TODO(falken): Change to DCHECK once https://crbug.com/655910 is resolved.
+  CHECK(registration->active_version());
   if (registration == associated_registration_) {
     SetControllerVersionAttribute(registration->active_version(),
                                   true /* notify_controllerchange */);

content/browser/service_worker/service_worker_provider_host.h

@@ -260,7 +260,8 @@ class CONTENT_EXPORT ServiceWorkerProviderHost
   // Called when our controller has been terminated and doomed due to an
   // exceptional condition like it could no longer be read from the script
   // cache.
-  void NotifyControllerLost();
+  void NotifyControllerLost(bool was_deleted);
+  bool controller_was_deleted() { return controller_was_deleted_; }
 
  private:
   friend class ForeignFetchRequestHandlerTest;
@@ -374,6 +375,8 @@ class CONTENT_EXPORT ServiceWorkerProviderHost
   base::WeakPtr<ServiceWorkerContextCore> context_;
   ServiceWorkerDispatcherHost* dispatcher_host_;
   bool allow_association_;
+  // TODO(falken): Remove once https://crbug.com/655910 is resolved.
+  bool controller_was_deleted_;
 
   std::vector<base::Closure> queued_events_;
 

content/browser/service_worker/service_worker_registration.cc

@@ -357,7 +357,7 @@ void ServiceWorkerRegistration::DeleteVersion(
        !it->IsAtEnd(); it->Advance()) {
     ServiceWorkerProviderHost* host = it->GetProviderHost();
     if (host->controlling_version() == version)
-      host->NotifyControllerLost();
+      host->NotifyControllerLost(true /* was_deleted */);
   }
 
   version->Doom();

content/browser/service_worker/service_worker_url_request_job_unittest.cc

@@ -291,7 +291,7 @@ class ServiceWorkerURLRequestJobTest
   void MainResourceLoadFailed() override {
     CHECK(provider_host_);
     // Detach the controller so subresource requests also skip the worker.
-    provider_host_->NotifyControllerLost();
+    provider_host_->NotifyControllerLost(false /* was_deleted */);
   }
 
   // Runs a request where the active worker starts a request in ACTIVATING state