Extension Storage API: expose storage quota information to extensions, via:

chrome/renderer/resources/extensions/schema_generated_bindings.js

Index: chrome/renderer/resources/extensions/schema_generated_bindings.js
diff --git a/chrome/renderer/resources/extensions/schema_generated_bindings.js b/chrome/renderer/resources/extensions/schema_generated_bindings.js
index 413476272c462cfa1d4e332edc3ff488334285c4..32c77017a953b7ed399d3cc59884e0ee79d712d0 100644
--- a/chrome/renderer/resources/extensions/schema_generated_bindings.js
+++ b/chrome/renderer/resources/extensions/schema_generated_bindings.js
@@ -493,6 +493,8 @@ var chrome = chrome || {};
                 // the constructor.
                 value = { __proto__: constructor.prototype };
                 constructor.apply(value, args);
+                // Recursively add properties.
+                addProperties(value, property);
               } else if (property.type === 'object') {
                 // Recursively add properties.
                 addProperties(value, property);