GuestView: Move lifetime management out of content

chrome/renderer/resources/extensions/app_view.js

 // Copyright 2014 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.
 
 var DocumentNatives = requireNative('document_natives');
 var GuestViewInternal =
     require('binding').Binding.create('guestViewInternal').generate();
 var IdGenerator = requireNative('id_generator');
 var guestViewInternalNatives = requireNative('guest_view_internal');
 
 function AppViewInternal(appviewNode) {
   privates(appviewNode).internal = this;
   this.appviewNode = appviewNode;
+  this.elementAttached = false;
+  this.pendingGuestCreation = false;
 
   this.browserPluginNode = this.createBrowserPluginNode();
   var shadowRoot = this.appviewNode.createShadowRoot();
   shadowRoot.appendChild(this.browserPluginNode);
   this.viewInstanceId = IdGenerator.GetNextId();
 }
 
 AppViewInternal.prototype.getErrorNode = function() {
   if (!this.errorNode) {
     this.errorNode = document.createElement('div');
@@ skipping 10 matching lines @@
 
 AppViewInternal.prototype.createBrowserPluginNode = function() {
   // We create BrowserPlugin as a custom element in order to observe changes
   // to attributes synchronously.
   var browserPluginNode = new AppViewInternal.BrowserPlugin();
   privates(browserPluginNode).internal = this;
   return browserPluginNode;
 };
 
 AppViewInternal.prototype.connect = function(app, data, callback) {
+  if (!this.elementAttached || this.pendingGuestCreation) {
+    if (callback) {
+      callback(false);
+    }
+    return;
+  }
   var createParams = {
     'appId': app,
     'data': data || {}
   };
-  var self = this;
   GuestViewInternal.createGuest(
     'appview',
     createParams,
     function(guestInstanceId) {
+      this.pendingGuestCreation = false;
+      if (guestInstanceId && !this.elementAttached) {
+        GuestViewInternal.destroyGuest(guestInstanceId);
+        guestInstanceId = 0;
+      }
       if (!guestInstanceId) {
         this.browserPluginNode.style.visibility = 'hidden';
         var errorMsg = 'Unable to connect to app "' + app + '".';
         window.console.warn(errorMsg);
         this.getErrorNode().innerText = errorMsg;
         if (callback) {
           callback(false);
         }
         return;
       }
       this.attachWindow(guestInstanceId);
       if (callback) {
         callback(true);
       }
     }.bind(this)
   );
+  this.pendingGuestCreation = true;
 };
 
 AppViewInternal.prototype.attachWindow = function(guestInstanceId) {
   this.guestInstanceId = guestInstanceId;
+  if (!this.internalInstanceId) {
+    return;
+  }
   var params = {
-    'instanceId': this.viewInstanceId,
+    'instanceId': this.viewInstanceId
   };
   this.browserPluginNode.style.visibility = 'visible';
   return guestViewInternalNatives.AttachGuest(
-      parseInt(this.browserPluginNode.getAttribute('internalinstanceid')),
+      this.internalInstanceId,
       guestInstanceId,
       params);
 };
 
+AppViewInternal.prototype.handleBrowserPluginAttributeMutation =
+    function(name, oldValue, newValue) {
+  if (name == 'internalinstanceid' && !oldValue && !!newValue) {
+    this.browserPluginNode.removeAttribute('internalinstanceid');
+    this.internalInstanceId = parseInt(newValue);
+
+    if (!!this.guestInstanceId && this.guestInstanceId != 0) {
+      var params = {
+        'instanceId': this.viewInstanceId
+      };
+      guestViewInternalNatives.AttachGuest(
+          this.internalInstanceId,
+          this.guestInstanceId,
+          params);
+    }
+    return;
+  }
+};
+
+AppViewInternal.prototype.reset = function() {
+  if (this.guestInstanceId) {
+    GuestViewInternal.destroyGuest(this.guestInstanceId);
+    this.guestInstanceId = undefined;
+  }
+};
+
 function registerBrowserPluginElement() {
   var proto = Object.create(HTMLObjectElement.prototype);
 
   proto.createdCallback = function() {
     this.setAttribute('type', 'application/browser-plugin');
     this.style.width = '100%';
     this.style.height = '100%';
   };
 
   proto.attachedCallback = function() {
     // Load the plugin immediately.
     var unused = this.nonExistentAttribute;
   };
 
+  proto.attributeChangedCallback = function(name, oldValue, newValue) {
+    var internal = privates(this).internal;
+    if (!internal) {
+      return;
+    }
+    internal.handleBrowserPluginAttributeMutation(name, oldValue, newValue);
+  };
+
   AppViewInternal.BrowserPlugin =
       DocumentNatives.RegisterElement('appplugin', {extends: 'object',
                                                     prototype: proto});
 
   delete proto.createdCallback;
   delete proto.attachedCallback;
   delete proto.detachedCallback;
   delete proto.attributeChangedCallback;
 }
 
 function registerAppViewElement() {
   var proto = Object.create(HTMLElement.prototype);
 
   proto.createdCallback = function() {
     new AppViewInternal(this);
   };
 
+  proto.attachedCallback = function() {
+    var internal = privates(this).internal;
+    if (!internal) {
+      return;
+    }
+    internal.elementAttached = true;
+  };
+
+  proto.detachedCallback = function() {
+    var internal = privates(this).internal;
+    if (!internal) {
+      return;
+    }
+    internal.elementAttached = false;
+    internal.reset();
+  };
+
   proto.connect = function() {
     var internal = privates(this).internal;
     $Function.apply(internal.connect, internal, arguments);
   }
+
   window.AppView =
       DocumentNatives.RegisterElement('appview', {prototype: proto});
 
   // Delete the callbacks so developers cannot call them and produce unexpected
   // behavior.
   delete proto.createdCallback;
   delete proto.attachedCallback;
   delete proto.detachedCallback;
   delete proto.attributeChangedCallback;
 }
 
 var useCapture = true;
 window.addEventListener('readystatechange', function listener(event) {
   if (document.readyState == 'loading')
     return;
 
   registerBrowserPluginElement();
   registerAppViewElement();
   window.removeEventListener(event.type, listener, useCapture);
 }, useCapture);