service worker: Add debugging CHECKs for a crash bug.

I suspect the linked crash bug is due to ServiceWorkerProviderHost
or ServiceWorkerHandle being deleted twice.

Bug: 838410
Change-Id: I695978c0d7fdbe96ac0eb411bc6cac80854c2079
Reviewed-on: https://chromium-review.googlesource.com/1056782Reviewed-by: Han Leon <leon.han@intel.com>
Commit-Queue: Matt Falkenhagen <falken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#558240}

content/browser/service_worker/service_worker_handle.cc

@@ -11,6 +11,7 @@
 #include "content/browser/service_worker/service_worker_type_converters.h"
 #include "content/common/service_worker/service_worker_types.h"
 #include "content/common/service_worker/service_worker_utils.h"
+#include "content/public/browser/browser_thread.h"
 #include "content/public/common/browser_side_navigation_policy.h"
 
 namespace content {
@@ -180,6 +181,12 @@ ServiceWorkerHandle::ServiceWorkerHandle(
 }
 
 ServiceWorkerHandle::~ServiceWorkerHandle() {
+  // TODO(crbug.com/838410): These CHECKs are temporary debugging for the linked
+  // bug.
+  CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  CHECK(!in_dtor_);
+  in_dtor_ = true;
+
   version_->RemoveListener(this);
 }
 

content/browser/service_worker/service_worker_handle.h

@@ -122,6 +122,9 @@ class CONTENT_EXPORT ServiceWorkerHandle
   mojo::AssociatedInterfacePtrSet<blink::mojom::ServiceWorkerObject>
       remote_objects_;
 
+  // TODO(crbug.com/838410): Temporary debugging for the linked bug.
+  bool in_dtor_ = false;
+
   base::WeakPtrFactory<ServiceWorkerHandle> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ServiceWorkerHandle);

content/browser/service_worker/service_worker_provider_host.cc

@@ -262,7 +262,12 @@ ServiceWorkerProviderHost::ServiceWorkerProviderHost(
 }
 
 ServiceWorkerProviderHost::~ServiceWorkerProviderHost() {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  // TODO(crbug.com/838410): The CHECKs are temporary debugging for the linked
+  // bug.
+  CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  CHECK(!in_dtor_);
+  in_dtor_ = true;
+
   if (context_)
     context_->UnregisterProviderHostByClientID(client_uuid_);
 

content/browser/service_worker/service_worker_provider_host.h

@@ -677,6 +677,9 @@ class CONTENT_EXPORT ServiceWorkerProviderHost
   // redirects.
   bool is_execution_ready_ = false;
 
+  // TODO(crbug.com/838410): Temporary debugging for the linked bug.
+  bool in_dtor_ = false;
+
   DISALLOW_COPY_AND_ASSIGN(ServiceWorkerProviderHost);
 };