Store per-origin metadata for localstorage.

content/browser/leveldb_wrapper_impl.h

Index: content/browser/leveldb_wrapper_impl.h
diff --git a/content/browser/leveldb_wrapper_impl.h b/content/browser/leveldb_wrapper_impl.h
index d350f9b2ca3ff3c1db39de691c401c393b532b1b..7bb6659b76494884921a222721c6850db87bb4c7 100644
--- a/content/browser/leveldb_wrapper_impl.h
+++ b/content/browser/leveldb_wrapper_impl.h
@@ -33,7 +33,8 @@ namespace content {
 class CONTENT_EXPORT LevelDBWrapperImpl : public mojom::LevelDBWrapper {
  public:
   using PrepareToCommitCallback =
-      base::Callback<std::vector<leveldb::mojom::BatchedOperationPtr>()>;
+      base::Callback<std::vector<leveldb::mojom::BatchedOperationPtr>(
+          const LevelDBWrapperImpl&)>;
 
   // |no_bindings_callback| will be called when this object has no more
   // bindings and all pending modifications have been processed.
@@ -49,6 +50,8 @@ class CONTENT_EXPORT LevelDBWrapperImpl : public mojom::LevelDBWrapper {
 
   void Bind(mojom::LevelDBWrapperRequest request);
 
+  size_t bytes_used() const { return bytes_used_; }
+
   // Commence aggressive flushing. This should be called early during startup,
   // before any localStorage writing. Currently scheduled writes will not be
   // rescheduled and will be flushed at the scheduled time after which