chromium : extensions, how a extension list on web store was installed to chrome

If you find a liked extension on chrome web store, you can install it just by simple click the "ADD TO CHROME" button.

Let's go deep into chromium codes, and see how it happened.
The key module is chrome.webstore, which a buildin JS object in chrome.
chrome/renderer/extensions/webstore_bindings.cc
chrome/renderer/extensions/webstore_bindings.h

WebstoreBindings::Install
TabHelper::DoInlineInstall
WebstoreInlineInstaller::BeginInstall
WebstoreStandaloneInstaller::ProceedWithInstallPrompt
ShowInstallUI

show install prompt dialog

WebstoreStandaloneInstaller::ProceedWithInstallPrompt
NavigationObserver::OnInstallPromptDone
ExtensionService::EnableExtension
ExtensionRegistrar::EnableExtension