Fix ExtensionServiceTest.ClearExtensionData flakiness

content/public/browser/storage_partition.h

Index: content/public/browser/storage_partition.h
diff --git a/content/public/browser/storage_partition.h b/content/public/browser/storage_partition.h
index 73ab62567edf5dde8cc833c72acbbfc0c4ed450b..fdce3b551be7f684c1382ee14aa5333eab930966 100644
--- a/content/public/browser/storage_partition.h
+++ b/content/public/browser/storage_partition.h
@@ -86,6 +86,8 @@ class CONTENT_EXPORT StoragePartition {
   // inside this StoragePartition for the given |storage_origin|.
   // Note session dom storage is not cleared even if you specify
   // REMOVE_DATA_MASK_LOCAL_STORAGE.
+  // |callback| is called when data deletion is done or at least the deletion is
+  // scheduled.
   //
   // TODO(ajwong): Right now, the embedder may have some
   // URLRequestContextGetter objects that the StoragePartition does not know
@@ -95,7 +97,8 @@ class CONTENT_EXPORT StoragePartition {
   virtual void ClearDataForOrigin(uint32 remove_mask,
                                   uint32 quota_storage_remove_mask,
                                   const GURL& storage_origin,
-                                  net::URLRequestContextGetter* rq_context) = 0;
+                                  net::URLRequestContextGetter* rq_context,
+                                  const base::Closure& callback) = 0;
 
   // A callback type to check if a given origin matches a storage policy.
   // Can be passed empty/null where used, which means the origin will always