Upstream injected JavaScript for the iOS web layer

ios/web/web_state/js/resources/message.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.
+
+// Scripts for the message handler.
+
+/**
+ * Namespace for this module.
+ */
+__gCrWeb.message = {};
+
+/* Beginning of anonymous object. */
+new function() {
+  /**
+   * Object to manage queue of messages waiting to be sent to the main
+   * application for immediate processing.
+   * @type {Object}
+   * @private
+   */
+  var immediateMessageQueue_ = {
+    scheme: 'crwebinvokeimmediate',
+    reset: function() {
+      immediateMessageQueue_.queue = [];
+      // Since the array will be JSON serialized, protect against non-standard
+      // custom versions of Array.prototype.toJSON.
+      immediateMessageQueue_.queue.toJSON = null;
+    }
+  };
+  immediateMessageQueue_.reset();
+
+  /**
+   * Object to manage queue of messages waiting to be sent to the main
+   * application for asynchronous processing.
+   * @type {Object}
+   * @private
+   */
+  var messageQueue_ = {
+    scheme: 'crwebinvoke',
+    reset: function() {
+      messageQueue_.queue = [];
+      // Since the array will be JSON serialized, protect against non-standard
+      // custom versions of Array.prototype.toJSON.
+      messageQueue_.queue.toJSON = null
+    }
+  };
+  messageQueue_.reset();
+
+  /**
+   * Invokes a command immediately on the Objective-C side.
+   * An immediate command is a special class of command that must be handled at
+   * the earliest opportunity. See the notes in CRWWebController for
+   * restrictions and precautions.
+   * @param {Object} command The command in a JavaScript object.
+   * @private
+   */
+  __gCrWeb.message.invokeOnHostImmediate = function(command) {
+    // If there is no document or body, the command will be silently dropped.
+    if (!document || !document.body)
+      return;
+    immediateMessageQueue_.queue.push(command);
+    sendQueue_(immediateMessageQueue_);
+  };
+
+  /**
+   * Invokes a command on the Objective-C side.
+   * @param {Object} command The command in a JavaScript object.
+   * @private
+   */
+  __gCrWeb.message.invokeOnHost = function(command) {
+    messageQueue_.queue.push(command);
+    sendQueue_(messageQueue_);
+  };
+
+  /**
+   * Returns the message queue as a string.
+   * @return {!Object} The current message queue.
+   */
+  __gCrWeb.message.getMessageQueue = function() {
+    var messageQueueString = __gCrWeb.common.JSONStringify(messageQueue_.queue);
+    messageQueue_.reset()
+    return messageQueueString;
+  };
+
+  /**
+   * Sends both queues if they contain messages.
+   */
+  __gCrWeb.message.invokeQueues = function() {
+    if (immediateMessageQueue_.queue.length > 0)
+      sendQueue_(immediateMessageQueue_);
+    if (messageQueue_.queue.length > 0)
+      sendQueue_(messageQueue_);
+  };
+
+  function sendQueue_(queueObject) {
+    // Do nothing if windowId has not been set.
+    if (!__gCrWeb.windowIdObject || typeof __gCrWeb.windowId != 'string') {
+      return;
+    }
+    // Some pages/plugins implement Object.prototype.toJSON, which can result
+    // in serializing messageQueue_ to an invalid format.
+    var originalObjectToJSON = Object.prototype.toJSON;
+    if (originalObjectToJSON)
+      delete Object.prototype.toJSON;
+    __gCrWeb.message_dynamic.sendQueue(queueObject);
+
+    if (originalObjectToJSON) {
+      // Restore Object.prototype.toJSON to prevent from breaking any
+      // functionality on the page that depends on its custom implementation.
+      Object.prototype.toJSON = originalObjectToJSON;
+    }
+  };
+}