Switch to mojo localstorage backend by default.

content/browser/dom_storage/local_storage_context_mojo.cc

Index: content/browser/dom_storage/local_storage_context_mojo.cc
diff --git a/content/browser/dom_storage/local_storage_context_mojo.cc b/content/browser/dom_storage/local_storage_context_mojo.cc
index 2be6213f8ce2f40c4be1d0821cb30765217a20f4..e32a02479cb1cacbcffc06a5165c84c027a93a80 100644
--- a/content/browser/dom_storage/local_storage_context_mojo.cc
+++ b/content/browser/dom_storage/local_storage_context_mojo.cc
@@ -388,7 +388,14 @@ void LocalStorageContextMojo::RunWhenConnected(base::OnceClosure callback) {
 
 void LocalStorageContextMojo::InitiateConnection(bool in_memory_only) {
   DCHECK_EQ(connection_state_, CONNECTION_IN_PROGRESS);
-  CHECK(connector_);
+
+  // Unit tests might not always have a Connector, use in-memory only if that
+  // happens.
+  if (!connector_) {
+    OnDatabaseOpened(false, leveldb::mojom::DatabaseError::OK);
+    return;
+  }
+
   if (!subdirectory_.empty() && !in_memory_only) {
     // We were given a subdirectory to write to. Get it and use a disk backed
     // database.
@@ -607,6 +614,13 @@ LevelDBWrapperImpl* LocalStorageContextMojo::GetOrCreateDBWrapper(
 
 void LocalStorageContextMojo::RetrieveStorageUsage(
     GetStorageUsageCallback callback) {
+  if (!database_) {
+    // If for whatever reason no leveldb database is available, no storage is
+    // used, so return an empty array.
+    std::move(callback).Run(std::vector<LocalStorageUsageInfo>());
+    return;
+  }
+
   database_->GetPrefixed(
       std::vector<uint8_t>(kMetaPrefix, kMetaPrefix + arraysize(kMetaPrefix)),
       base::Bind(&LocalStorageContextMojo::OnGotMetaData,