Add uma stats to help evaluate the impact of changes to the quota allocation logic.

components/leveldb/env_mojo.h

Index: components/leveldb/env_mojo.h
diff --git a/components/leveldb/env_mojo.h b/components/leveldb/env_mojo.h
index 569bcfe5ccb9e1eb0238acafa2571c46c229dfa8..ca0f683902e04a892ceec519b32a75fbff47ebb1 100644
--- a/components/leveldb/env_mojo.h
+++ b/components/leveldb/env_mojo.h
@@ -54,6 +54,8 @@ class MojoEnv : public Env, public leveldb_env::UMALogger {
   void RecordErrorAt(leveldb_env::MethodID method) const override;
   void RecordOSError(leveldb_env::MethodID method,
                      base::File::Error error) const override;
+  void RecordBytesRead(int amount) const override;
+  void RecordBytesWritten(int amount) const override;
 
   void RecordFileError(leveldb_env::MethodID method,
                        filesystem::mojom::FileError error) const;