Add stub Mojo interface for StoragePartition that's reachable from the renderer.

BUG=586194

Review URL: https://codereview.chromium.org/1697463003

Cr-Commit-Position: refs/heads/master@{#377362}
diff --git a/content/common/BUILD.gn b/content/common/BUILD.gn
index 157b932..45c63a6 100644
--- a/content/common/BUILD.gn
+++ b/content/common/BUILD.gn
@@ -532,6 +532,7 @@
     "background_sync_service.mojom",
     "geolocation_service.mojom",
     "image_downloader/image_downloader.mojom",
+    "leveldb_wrapper.mojom",
     "permission_service.mojom",
     "presentation/presentation_service.mojom",
     "process_control.mojom",
@@ -539,6 +540,7 @@
     "render_widget_window_tree_client_factory.mojom",
     "service_port_service.mojom",
     "service_worker/embedded_worker_setup.mojom",
+    "storage_partition_service.mojom",
     "vr_service.mojom",
     "wake_lock_service.mojom",
   ]
@@ -546,6 +548,7 @@
   import_dirs = [ "//mojo/services" ]
 
   public_deps = [
+    "//components/leveldb/public/interfaces",
     "//components/mus/public/interfaces",
     "//content/public/common:mojo_bindings",
     "//mojo/shell/public/interfaces",