Keep track of ServiceWorkerContext's BrowserContext and expose it.

content/browser/service_worker/service_worker_context_wrapper.h

Index: content/browser/service_worker/service_worker_context_wrapper.h
diff --git a/content/browser/service_worker/service_worker_context_wrapper.h b/content/browser/service_worker/service_worker_context_wrapper.h
index 56367eee1cebbe645a0e4dc537f57aa68eec1d45..9d062d4e049015fd27d074368adcbed4b4a4704e 100644
--- a/content/browser/service_worker/service_worker_context_wrapper.h
+++ b/content/browser/service_worker/service_worker_context_wrapper.h
@@ -35,6 +35,7 @@ class BrowserContext;
 class ChromeBlobStorageContext;
 class ServiceWorkerContextCore;
 class ServiceWorkerContextObserver;
+class StoragePartitionImpl;
 
 // A refcounted wrapper class for our core object. Higher level content lib
 // classes keep references to this class on mutliple threads. The inner core
@@ -48,7 +49,8 @@ class CONTENT_EXPORT ServiceWorkerContextWrapper
 
   // Init and Shutdown are for use on the UI thread when the profile,
   // storagepartition is being setup and torn down.
-  void Init(const base::FilePath& user_data_directory,
+  void Init(StoragePartitionImpl* storage_partition,
+            const base::FilePath& user_data_directory,
             storage::QuotaManagerProxy* quota_manager_proxy,
             storage::SpecialStoragePolicy* special_storage_policy);
   void Shutdown();
@@ -61,6 +63,9 @@ class CONTENT_EXPORT ServiceWorkerContextWrapper
   // The core context is only for use on the IO thread.
   ServiceWorkerContextCore* context();
 
+  // The StoragePartition should only be used on the UI thread.

[michaeln, 2015/01/13 21:27:32]

Also say that it may be null before/during init and during/after shutdown.

[mlamouri (slow - plz ping), 2015/01/14 15:46:24]

Done.

+  StoragePartitionImpl* storage_partition() const;
+
   // The process manager can be used on either UI or IO.
   ServiceWorkerProcessManager* process_manager() {
     return process_manager_.get();
@@ -130,6 +135,9 @@ class CONTENT_EXPORT ServiceWorkerContextWrapper
 
   // Initialized in Init(); true if the user data directory is empty.
   bool is_incognito_;
+
+  // WeakPtr to the StoragePartitionImpl owning |this|.

[michaeln, 2015/01/13 21:27:32]

Actual use of the WeakPtr<> template here might help catch programming errors
that try to access it on the wrong thread.

[mlamouri (slow - plz ping), 2015/01/14 15:46:24]

I would prefer not to abuse WeakPtr<> in order to simply have a thread safe
object unless this is a common pattern already? Would that be interesting to add
such a wrapper in a follow-up? ie. something that would guarantee that object X
is only used on thread Y.

+  StoragePartitionImpl* storage_partition_;
 };
 
 }  // namespace content