[extension SW] Support lazy events from extension service workers.

extensions/browser/service_worker_task_queue.cc

+// Copyright 2017 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 "extensions/browser/service_worker_task_queue.h"
+
+#include "content/public/browser/browser_context.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/render_process_host.h"
+#include "content/public/browser/service_worker_context.h"
+#include "content/public/browser/storage_partition.h"
+#include "extensions/browser/event_router.h"
+#include "extensions/browser/lazy_context_id.h"
+#include "extensions/browser/service_worker_task_queue_factory.h"
+#include "extensions/common/constants.h"
+
+using content::BrowserContext;
+using content::BrowserThread;
+
+namespace extensions {
+
+namespace {
+
+void FinishTask(const LazyContextTaskQueue::PendingTask& task,
+                const ExtensionId& extension_id,
+                int process_id,
+                int thread_id) {
+  auto params = base::MakeUnique<LazyContextTaskQueue::ContextInfo>(
+      extension_id, content::RenderProcessHost::FromID(process_id), thread_id,
+      GURL());
+  task.Run(std::move(params));
+}
+
+void GotWorkerInfoOnIO(const LazyContextTaskQueue::PendingTask& task,

[Devlin, 2017/06/20 20:31:20]

nit: Get and Got are pretty similar for both reading and typing.  Could we have
Get and DidGet to differentiate them slightly more?

[lazyboy, 2017/06/22 02:46:57]

Done.

+                       const ExtensionId& extension_id,
+                       int process_id,
+                       int thread_id) {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::IO);
+  content::BrowserThread::PostTask(
+      content::BrowserThread::UI, FROM_HERE,
+      base::Bind(FinishTask, task, extension_id, process_id, thread_id));
+}
+
+void GetWorkerInfoFailed() {
+  DCHECK(false) << "GetWorkerInfoFailed";
+  // TODO(lazyboy): Handle failure case.
+}
+
+void GetServiceWorkerInfoOnIO(
+    const GURL& origin,
+    const ExtensionId& extension_id,
+    content::ServiceWorkerContext* service_worker_context,
+    const LazyContextTaskQueue::PendingTask& task) {
+  service_worker_context->GetWorkerInfoAfterStartWorker(
+      origin, base::BindOnce(&GotWorkerInfoOnIO, task, extension_id),
+      base::BindOnce(&GetWorkerInfoFailed));
+}
+
+}  // namespace
+
+ServiceWorkerTaskQueue::ServiceWorkerTaskQueue(
+    content::BrowserContext* browser_context) {}
+
+ServiceWorkerTaskQueue::~ServiceWorkerTaskQueue() {}
+
+// static
+ServiceWorkerTaskQueue* ServiceWorkerTaskQueue::Get(
+    content::BrowserContext* context) {
+  return ServiceWorkerTaskQueueFactory::GetForBrowserContext(context);
+}
+
+bool ServiceWorkerTaskQueue::ShouldEnqueueTask(content::BrowserContext* context,
+                                               const Extension* extension) {
+  // We call StartWorker every time we want to dispatch an event to an extension
+  // Service worker.
+  // TODO(lazyboy): Is that a problem?
+  return true;
+}
+
+void ServiceWorkerTaskQueue::AddPendingTaskToDispatchEvent(
+    LazyContextId* context_id,
+    const LazyContextTaskQueue::PendingTask& task) {
+  DCHECK(context_id->is_for_service_worker());
+  content::StoragePartition* partition =
+      BrowserContext::GetStoragePartitionForSite(
+          context_id->browser_context(), context_id->service_worker_scope());
+  content::ServiceWorkerContext* service_worker_context =
+      partition->GetServiceWorkerContext();
+
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&GetServiceWorkerInfoOnIO, context_id->service_worker_scope(),
+                 context_id->extension_id(), service_worker_context, task));
+}
+
+}  // namespace extensions