Enable posting a message from JS to Android webview.

android_webview/common/aw_message_port_messages.h

Index: android_webview/common/aw_message_port_messages.h
diff --git a/android_webview/common/aw_message_port_messages.h b/android_webview/common/aw_message_port_messages.h
new file mode 100644
index 0000000000000000000000000000000000000000..1700536709f78f8a975f662f02c3eb5ba9ad6ac6
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+++ b/android_webview/common/aw_message_port_messages.h
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+// Copyright (c) 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.
+
+// Multiply-included file, no traditional include guard.
+#include <vector>
+
+#include "base/basictypes.h"
+#include "ipc/ipc_message_macros.h"
+
+#define IPC_MESSAGE_START AwMessagePortMsgStart
+
+//-----------------------------------------------------------------------------
+// MessagePort messages
+// These are messages sent from the browser to the renderer process.
+
+// Tells the renderer to convert the sent message from a WebSerializeScript
+// format to a base::Value. Due to the complexities of renderer/browser
+// relation, this can only be done in renderer for now.
+IPC_MESSAGE_ROUTED3(AwMessagePortMsg_Message,
+                    int /* recipient message port id */,
+                    base::string16 /* message */,
+                    std::vector<int> /* sent message port_ids */)
+
+//-----------------------------------------------------------------------------
+// These are messages sent from the renderer to the browser process.
+
+// Response to AwMessagePortMessage_ConvertMessage
+IPC_MESSAGE_ROUTED3(AwMessagePortHostMsg_ConvertedMessage,
+                     int /* recipient message port id */,
+                     base::ListValue /* converted message */,
+                     std::vector<int> /* sent message port_ids */)