Enable posting a message from JS to Android webview.

android_webview/browser/aw_message_port_message_filter.h

Index: android_webview/browser/aw_message_port_message_filter.h
diff --git a/android_webview/browser/aw_message_port_message_filter.h b/android_webview/browser/aw_message_port_message_filter.h
new file mode 100644
index 0000000000000000000000000000000000000000..8227b21aebdc5b5d6d9484e4f5705b8541e4cde8
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+// 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.
+
+#ifndef ANDROID_WEBVIEW_BROWSER_MESSAGE_PORT_MESSAGE_FILTER_H_
+#define ANDROID_WEBVIEW_BROWSER_MESSAGE_PORT_MESSAGE_FILTER_H_
+
+#include "base/callback.h"
+#include "content/public/browser/browser_message_filter.h"
+#include "content/public/browser/message_port_delegate.h"
+
+namespace android_webview {
+
+// Filter for Aw specific MessagePort related IPC messages (creating and
+// destroying a MessagePort, sending a message via a MessagePort etc).
+class AwMessagePortMessageFilter : public content::BrowserMessageFilter,
+                                   public content::MessagePortDelegate {
+ public:
+  AwMessagePortMessageFilter(int routing_id);
+
+  // BrowserMessageFilter implementation.
+  void OnChannelClosing() override;
+  bool OnMessageReceived(const IPC::Message& message) override;
+  void OnDestruct() const override;
+
+  // MessagePortDelegate implementation.
+  void SendMessage(int msg_port_route_id,
+                   const base::string16& message,
+                   const std::vector<int>& sent_message_port_ids) override;
+  void SendMessagesAreQueued(int route_id) override;
+
+ private:
+  friend class content::BrowserThread;
+  friend class base::DeleteHelper<AwMessagePortMessageFilter>;
+
+  ~AwMessagePortMessageFilter() override;
+
+  int route_id_;
+
+  DISALLOW_COPY_AND_ASSIGN(AwMessagePortMessageFilter);
+};
+
+}   // namespace android_webview
+
+#endif  // ANDROID_WEBVIEW_BROWSER_MESSAGE_PORT_MESSAGE_FILTER_H_
+