Pass the size to the RenderView on creation.

extensions/test/data/web_view/apitest/main.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 embedder = {};
 
 // TODO(lfg) Move these functions to a common js.
 embedder.setUp_ = function(config) {
   if (!config || !config.testServer) {
     return;
@@ skipping 204 matching lines @@
 function testAutosizeBeforeNavigation() {
   var webview = document.createElement('webview');
 
   webview.setAttribute('autosize', 'true');
   webview.setAttribute('minwidth', 200);
   webview.setAttribute('maxwidth', 210);
   webview.setAttribute('minheight', 100);
   webview.setAttribute('maxheight', 110);
 
   webview.addEventListener('sizechanged', function(e) {
-    embedder.test.assertEq(0, e.oldWidth);
-    embedder.test.assertEq(0, e.oldHeight);
     embedder.test.assertTrue(e.newWidth >= 200 && e.newWidth <= 210);
     embedder.test.assertTrue(e.newHeight >= 100 && e.newHeight <= 110);
     embedder.test.succeed();
   });
 
   webview.setAttribute('src', 'data:text/html,webview test sizechanged event');
   document.body.appendChild(webview);
 }
 
 // This test verifies that a lengthy page with autosize enabled will report
 // the correct height in the sizechanged event.
 function testAutosizeHeight() {
   var webview = document.createElement('webview');
 
   webview.autosize = true;
   webview.minwidth = 200;
   webview.maxwidth = 210;
   webview.minheight = 40;
   webview.maxheight = 200;
 
   var step = 1;
   webview.addEventListener('sizechanged', function(e) {
     switch (step) {
       case 1:
-        embedder.test.assertEq(0, e.oldHeight);
         embedder.test.assertEq(200, e.newHeight);
         // Change the maxheight to verify that we see the change.
         webview.maxheight = 50;
         break;
       case 2:
         embedder.test.assertEq(200, e.oldHeight);
         embedder.test.assertEq(50, e.newHeight);
         embedder.test.succeed();
         break;
       default:
@@ skipping 1464 matching lines @@
   'testWebRequestAPIExistence': testWebRequestAPIExistence,
   'testWebRequestAPIGoogleProperty': testWebRequestAPIGoogleProperty
 };
 
 onload = function() {
   chrome.test.getConfig(function(config) {
     embedder.setUp_(config);
     chrome.test.sendMessage('LAUNCHED');
   });
 };