<webview>: Implement dialog API

chrome/test/data/extensions/platform_apps/web_view/dialog/inject_dialog.js

+// 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.
+
+var embedder = null;
+
+function reportConnected() {
+  var msg = ['connected'];
+  embedder.postMessage(JSON.stringify(msg), '*');
+}
+
+function reportAlertCompletion(messageText) {
+  window.alert(messageText);
+  var msg = ['alert-dialog-done'];
+  embedder.postMessage(JSON.stringify(msg), '*');
+}
+
+function reportConfirmDialogResult(messageText) {
+  var result = window.confirm(messageText);
+  var msg = ['confirm-dialog-result', result];
+  embedder.postMessage(JSON.stringify(msg), '*');
+}
+
+function reportPromptDialogResult(messageText, defaultPromptText) {
+  var result = window.prompt(messageText, defaultPromptText);
+  var msg = ['prompt-dialog-result', result];
+  embedder.postMessage(JSON.stringify(msg), '*');
+}
+
+window.addEventListener('message', function(e) {
+  embedder = e.source;
+  var data = JSON.parse(e.data);
+  switch (data[0]) {
+    case 'connect': {
+      reportConnected();
+      break;
+    }
+    case 'start-confirm-dialog-test': {
+      var messageText = data[1];
+      reportConfirmDialogResult(messageText);
+      break;
+    }
+    case 'start-alert-dialog-test': {
+      var messageText = data[1];
+      reportAlertCompletion(messageText);
+      break;
+    }
+    case 'start-prompt-dialog-test': {
+      var messageText = data[1];
+      var defaultPromptText = data[2];
+      reportPromptDialogResult(messageText, defaultPromptText);
+      break;
+    }
+  }
+});