[Extensions Bindings] Add chrome.runtime.lastError support

extensions/renderer/native_extension_bindings_system.h

Index: extensions/renderer/native_extension_bindings_system.h
diff --git a/extensions/renderer/native_extension_bindings_system.h b/extensions/renderer/native_extension_bindings_system.h
index da55d76acaa9a003a4b71d7b215a7ef6ab6483a3..7305b89b3bf178cd80c7ce6bc7df7d7cfd3f0f08 100644
--- a/extensions/renderer/native_extension_bindings_system.h
+++ b/extensions/renderer/native_extension_bindings_system.h
@@ -68,8 +68,15 @@ class NativeExtensionBindingsSystem : public ExtensionBindingsSystem {
                               v8::Local<v8::Context> context);
 
   // Getter callback for an extension API, since APIs are constructed lazily.
-  static void GetAPIHelper(v8::Local<v8::Name> name,
-                           const v8::PropertyCallbackInfo<v8::Value>& info);
+  static void BindingAccessor(v8::Local<v8::Name> name,
+                              const v8::PropertyCallbackInfo<v8::Value>& info);
+
+  // Creates and returns the API binding for the given |name|.
+  static v8::Local<v8::Object> GetAPIHelper(v8::Local<v8::Context> context,
+                                            v8::Local<v8::String> name);
+
+  // Gets the chrome.runtime API binding.
+  static v8::Local<v8::Object> GetRuntime(v8::Local<v8::Context> context);
 
   // Handler to send request IPCs. Abstracted out for testing purposes.
   SendRequestIPCMethod send_request_ipc_;