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

chrome/renderer/resources/extensions/webstore_custom_bindings.js

 // Copyright (c) 2012 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.
 
 // Custom binding for the webstore API.
 
 var webstoreNatives = requireNative('webstore');
 
 function Installer() {
   this._pendingInstall = null;
+  this._installStageListener = null;
+  this._downloadProgressListener = null;
 }
 
 Installer.prototype.install = function(url, onSuccess, onFailure) {
   if (this._pendingInstall)
     throw 'A Chrome Web Store installation is already pending.';
-  var installId = webstoreNatives.Install(url, onSuccess, onFailure);
+  var installId = webstoreNatives.Install(
+      this._installStageListener != null,
+      this._downloadProgressListener != null,

[not at google - send to devlin, 2014/02/27 21:49:56]

you can also do !!this._installStageListener etc.

[Devlin, 2014/02/28 18:04:51]

(replaced with event.hasListeners())

+      url,
+      onSuccess,
+      onFailure);
   if (installId !== undefined) {
     this._pendingInstall = {
       installId: installId,
       onSuccess: onSuccess,
       onFailure: onFailure
     };
   }
 };
 
 Installer.prototype.onInstallResponse = function(installId, success, error) {
   var pendingInstall = this._pendingInstall;
   if (!pendingInstall || pendingInstall.installId != installId) {
     // TODO(kalman): should this be an error?
     return;
   }
 
   try {
     if (success && pendingInstall.onSuccess)
       pendingInstall.onSuccess();
     else if (!success && pendingInstall.onFailure)
       pendingInstall.onFailure(error);
   } catch (e) {
     console.error('Exception in chrome.webstore.install response handler: ' +
                   e.stack);
   } finally {
     this._pendingInstall = null;
   }
 };
 
+Installer.prototype.setInstallStageListener = function(callback) {
+  if (webstoreNatives.ValidateInstallStageListener(callback))
+    this._installStageListener = callback;
+};
+
+Installer.prototype.onInstallStageChanged = function(installStage) {
+  if (!this._installStageListener)
+    return;  // This could happen if we removed the listener mid-flight.
+
+  try {
+    this._installStageListener(installStage);
+  } catch (e) {
+    console.error('Exception in listener set by ' +
+                  'chrome.webstore.setInstallStageListener: ' +
+                  e.message + ', ' + e.stack);
+  }
+};
+
+Installer.prototype.setDownloadProgressListener = function(callback) {
+  if (webstoreNatives.ValidateDownloadProgressListener(callback))
+    this._downloadProgressListener = callback;
+};
+
+Installer.prototype.onDownloadProgress = function(progress) {
+  if (!this._downloadProgressListener)
+    return;  // This could happen if we removed the listener mid-flight.
+
+  try {
+    this._downloadProgressListener(progress);
+  } catch (e) {
+    console.error('Exception in listener set by ' +
+                  'chrome.webstore.setDownloadProgressListener: ' +
+                  e.message + ', ' + e.stack);
+  }
+};
+
 var installer = new Installer();
 
 var chromeWebstore = {
-  install: function install(url, onSuccess, onFailure) {
+  install: function (url, onSuccess, onFailure) {
     installer.install(url, onSuccess, onFailure);
+  },
+  setInstallStageListener: function (callback) {
+    installer.setInstallStageListener(callback);
+  },
+  setDownloadProgressListener: function (callback) {
+    installer.setDownloadProgressListener(callback);
   }

[not at google - send to devlin, 2014/02/27 21:49:56]

see comment in the JSON which applies here too. you should be able to create
"anonymous" events with "new Event()" and then fire events on them yourself. See
how the messaging stuff works.

[Devlin, 2014/02/28 18:04:51]

Done.

 };
 
-// Called by webstore_binding.cc.
-function onInstallResponse(installId, success, error) {
-  installer.onInstallResponse(installId, success, error);
-}
-
-// These must match the names in InstallWebstorebinding in
+// This must match the name in InstallWebstoreBindings in
 // chrome/renderer/extensions/dispatcher.cc.
 exports.chromeWebstore = chromeWebstore;
-exports.onInstallResponse = onInstallResponse;
+
+// Called by webstore_binding.cc.
+exports.onInstallResponse =
+    Installer.prototype.onInstallResponse.bind(installer);
+exports.onInstallStageChanged =
+    Installer.prototype.onInstallStageChanged.bind(installer);
+exports.onDownloadProgress =
+    Installer.prototype.onDownloadProgress.bind(installer);