<webview>: Move back, forward, canGoBack, canGoForward, go from content to chrome

chrome/renderer/resources/extensions/web_view.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.
 
 // Shim that simulates a <webview> tag via Mutation Observers.
 //
 // The actual tag is implemented via the browser plugin. The internals of this
 // are hidden via Shadow DOM.
 
 var watchForTag = require('tagWatcher').watchForTag;
 var eventBindings = require('event_bindings');
 
 /** @type {Array.<string>} */
 var WEB_VIEW_ATTRIBUTES = ['name', 'src', 'partition', 'autosize', 'minheight',
     'minwidth', 'maxheight', 'maxwidth'];
 
 
 // All exposed api methods for <webview>, these are forwarded to the browser
 // plugin.
 var WEB_VIEW_API_METHODS = [
-  'back',
-  'canGoBack',
-  'canGoForward',
-  'forward',
   'getProcessId',
-  'go',
   'reload',
   'stop',
   'terminate'
 ];
 
 var WEB_VIEW_EVENTS = {
   'close': [],
   'consolemessage': ['level', 'message', 'line', 'sourceId'],
   'contentload' : [],
   'exit' : ['processId', 'reason'],
@@ skipping 24 matching lines @@
 window.addEventListener('readystatechange', function(e) {
   if (document.readyState != 'loading') {
     return;
   }
 
   document.addEventListener('DOMContentLoaded', function(e) {
     watchForTag('WEBVIEW', function(addedNode) { new WebView(addedNode); });
   });
 }, true /* useCapture */);
 
+
+/** @type {number} */
+WebView.prototype.entryCount_;
+
+/** @type {number} */
+WebView.prototype.currentEntryIndex_;
+
 /**
  * @constructor
  */
 function WebView(webviewNode) {
   this.webviewNode_ = webviewNode;
   this.browserPluginNode_ = this.createBrowserPluginNode_();
   var shadowRoot = this.webviewNode_.webkitCreateShadowRoot();
   shadowRoot.appendChild(this.browserPluginNode_);
 
   this.setupFocusPropagation_();
@@ skipping 56 matching lines @@
     self.browserPluginNode_.blur();
   });
 };
 
 /**
  * @private
  */
 WebView.prototype.setupWebviewNodeMethods_ = function() {
   // this.browserPluginNode_[apiMethod] are not necessarily defined immediately
   // after the shadow object is appended to the shadow root.
+  var webviewNode = this.webviewNode_;
+  var browserPluginNode = this.browserPluginNode_;
   var self = this;
+
+  webviewNode['canGoBack'] = function() {
+    return self.entryCount_ > 1 && self.currentEntryIndex_ > 0;
+  };
+
+  webviewNode['canGoForward'] = function() {
+    return self.currentEntryIndex_ >=0 &&
+        self.currentEntryIndex_ < (self.entryCount_ - 1);
+  };
+
+  webviewNode['back'] = function() {
+    webviewNode.go(-1);
+  };
+
+  webviewNode['forward'] = function() {
+    webviewNode.go(1);
+  };
+
+  webviewNode['go'] = function(relativeIndex) {
+    var instanceId = browserPluginNode.getGuestInstanceId();
+    if (!instanceId)
+      return;
+    chrome.webview.go(instanceId, relativeIndex);
+  };
+
   $Array.forEach(WEB_VIEW_API_METHODS, function(apiMethod) {
-    self.webviewNode_[apiMethod] = function(var_args) {
-      return $Function.apply(self.browserPluginNode_[apiMethod],
-          self.browserPluginNode_, arguments);
+    webviewNode[apiMethod] = function(var_args) {
+      return browserPluginNode[apiMethod].apply(browserPluginNode, arguments);
     };
   }, this);
   this.setupExecuteCodeAPI_();
 };
 
 /**
  * @private
  */
 WebView.prototype.setupWebviewNodeProperties_ = function() {
   var ERROR_MSG_CONTENTWINDOW_NOT_AVAILABLE = '<webview>: ' +
@@ skipping 105 matching lines @@
     if (newValue != oldValue) {
       this.webviewNode_.setAttribute(mutation.attributeName, newValue);
     }
   }
 };
 
 /**
  * @private
  */
 WebView.prototype.setupWebviewNodeEvents_ = function() {
+  var self = this;
   var webviewNode = this.webviewNode_;
   // TODO(fsamuel): Generalize this further as we add more events.
   var onAttached = function(e) {
     var detail = e.detail ? JSON.parse(e.detail) : {};
     loadCommitEvent.addListener(function(event) {
       var webviewEvent = new Event('loadcommit', {bubbles: true});
       var attribs = WEB_VIEW_EVENTS['loadcommit'];
       $Array.forEach(attribs, function(attribName) {
         webviewEvent[attribName] = event[attribName];
       });
+      self.currentEntryIndex_ = event.currentEntryIndex;
+      self.entryCount_ = event.entryCount;
       webviewNode.dispatchEvent(webviewEvent);
     }, {instanceId: detail.windowId});
   };
   this.browserPluginNode_.addEventListener('-internal-attached', onAttached);
 
   for (var eventName in WEB_VIEW_EVENTS) {
     this.setupEvent_(eventName, WEB_VIEW_EVENTS[eventName]);
   }
   this.setupNewWindowEvent_();
   this.setupPermissionEvent_();
@@ skipping 212 matching lines @@
   return [];
 };
 
 /**
  * Implemented when the experimental API is available.
  * @private
  */
 WebView.prototype.maybeSetupExperimentalAPI_ = function() {};
 
 exports.WebView = WebView;