Keep track of ServiceWorkerContext's BrowserContext and expose it.

content/browser/service_worker/service_worker_context_core.cc

Index: content/browser/service_worker/service_worker_context_core.cc
diff --git a/content/browser/service_worker/service_worker_context_core.cc b/content/browser/service_worker/service_worker_context_core.cc
index 51baeb650f08c0bd25959a671bb9bc0f35532db9..256eb6fbeb8dede22740089768cd5348ef5cb91d 100644
--- a/content/browser/service_worker/service_worker_context_core.cc
+++ b/content/browser/service_worker/service_worker_context_core.cc
@@ -22,6 +22,7 @@
 #include "content/browser/service_worker/service_worker_register_job.h"
 #include "content/browser/service_worker/service_worker_registration.h"
 #include "content/browser/service_worker/service_worker_storage.h"
+#include "content/browser/storage_partition_impl.h"
 #include "content/public/browser/browser_thread.h"
 #include "storage/browser/quota/quota_manager_proxy.h"
 #include "url/gurl.h"
@@ -435,6 +436,13 @@ void ServiceWorkerContextCore::TransferProviderHostIn(
   delete temp;
 }
 
+BrowserContext* ServiceWorkerContextCore::GetBrowserContext() const {
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
+  if (!wrapper_->storage_partition())
+    return nullptr;
+  return wrapper_->storage_partition()->browser_context();
+}
+
 void ServiceWorkerContextCore::OnWorkerStarted(ServiceWorkerVersion* version) {
   if (!observer_list_.get())
     return;
@@ -497,9 +505,7 @@ void ServiceWorkerContextCore::OnReportConsoleMessage(
 }
 
 ServiceWorkerProcessManager* ServiceWorkerContextCore::process_manager() {
-  if (wrapper_)
-    return wrapper_->process_manager();
-  return NULL;
+  return wrapper_->process_manager();
 }
 
 }  // namespace content