Add chrome.webstore API methods to allow sites to see progress of installation

chrome/browser/extensions/install_observer.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/extensions/install_observer.h"
 
 namespace extensions {
 
 InstallObserver::ExtensionInstallParams::ExtensionInstallParams(
     std::string extension_id,
     std::string extension_name,
     gfx::ImageSkia installing_icon,
     bool is_app,
     bool is_platform_app)
         : extension_id(extension_id),
           extension_name(extension_name),
           installing_icon(installing_icon),
           is_app(is_app),
           is_platform_app(is_platform_app),
           is_ephemeral(false) {}
 
+void InstallObserver::OnBeginExtensionInstall(
+    const ExtensionInstallParams& params) {}
+void InstallObserver::OnBeginExtensionDownload(
+    const std::string& extension_id) {}
+void InstallObserver::OnDownloadProgress(const std::string& extension_id,
+                                         int percent_downloaded) {}
+void InstallObserver::OnBeginCrxInstall(const std::string& extension_id) {}
+void InstallObserver::OnInstallFailure(const std::string& extension_id) {}
+void InstallObserver::OnExtensionInstalled(const Extension* extension) {}
+void InstallObserver::OnExtensionLoaded(const Extension* extension) {}
+void InstallObserver::OnExtensionUnloaded(const Extension* extension) {}
+void InstallObserver::OnExtensionUninstalled(const Extension* extension) {}
+void InstallObserver::OnAppInstalledToAppList(const std::string& extension_id) {
+}
+void InstallObserver::OnAppsReordered() {}
+void InstallObserver::OnShutdown() {}
+
 }  // namespace extensions