[Android] Java Bridge with Gin: implement Java Bridge dispatcher

content/common/gin_java_bridge_messages.h

 // 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.
 
 // IPC messages for injected Java objects (Gin-based implementation).
 
 // Multiply-included message file, hence no include guard.
 
 #include "base/basictypes.h"
+#include "content/common/android/gin_java_bridge_errors.h"
 #include "content/common/content_export.h"
 #include "ipc/ipc_message_macros.h"
 
 #undef IPC_MESSAGE_EXPORT
 #define IPC_MESSAGE_EXPORT CONTENT_EXPORT
 #define IPC_MESSAGE_START GinJavaBridgeMsgStart
 
 // Messages for handling Java objects injected into JavaScript -----------------
 
+IPC_ENUM_TRAITS(content::GinJavaBridgeError)
+
 // Sent from browser to renderer to add a Java object with the given name.
 // Object IDs are generated on the browser side.
 IPC_MESSAGE_ROUTED2(GinJavaBridgeMsg_AddNamedObject,
                     std::string /* name */,
                     int32 /* object_id */)
 
 // Sent from browser to renderer to remove a Java object with the given name.
 IPC_MESSAGE_ROUTED1(GinJavaBridgeMsg_RemoveNamedObject,
                     std::string /* name */)
 
 // Sent from renderer to browser to get information about methods of
 // the given object. The query will only succeed if inspection of injected
 // objects is enabled on the browser side.
 IPC_SYNC_MESSAGE_ROUTED1_1(GinJavaBridgeHostMsg_GetMethods,
                            int32 /* object_id */,
                            std::set<std::string> /* returned_method_names */)
 
 // Sent from renderer to browser to find out, if an object has a method with
 // the given name.
 IPC_SYNC_MESSAGE_ROUTED2_1(GinJavaBridgeHostMsg_HasMethod,
                            int32 /* object_id */,
                            std::string /* method_name */,
                            bool /* result */)
 
 // Sent from renderer to browser to invoke a method. Method arguments
 // are chained into |arguments| list. base::ListValue is used for |result| as
 // a container to work around immutability of base::Value.
 // Empty result list indicates that an error has happened on the Java side
 // (either bridge-induced error or an unhandled Java exception) and an exception
-// must be thrown into JavaScript.
+// must be thrown into JavaScript. |error_code| indicates the cause of
+// the error.
 // Some special value types that are not supported by base::Value are encoded
 // as BinaryValues via GinJavaBridgeValue.
-IPC_SYNC_MESSAGE_ROUTED3_1(GinJavaBridgeHostMsg_InvokeMethod,
+IPC_SYNC_MESSAGE_ROUTED3_2(GinJavaBridgeHostMsg_InvokeMethod,
                            int32 /* object_id */,
                            std::string /* method_name */,
                            base::ListValue /* arguments */,
-                           base::ListValue /* result */)
+                           base::ListValue /* result */,
+                           content::GinJavaBridgeError /* error_code */)
 
 // Sent from renderer to browser in two cases:
 //
 //  1. (Main usage) To inform that the JS wrapper of the object has
 //     been completely dereferenced and garbage-collected.
 //
 //  2. To notify the browser that wrapper creation has failed.  The browser side
 //     assumes optimistically that every time an object is returned from a
 //     method, the corresponding wrapper object will be successfully created on
 //     the renderer side. Sending of this message informs the browser whether
 //     this expectation has failed.
 IPC_MESSAGE_ROUTED1(GinJavaBridgeHostMsg_ObjectWrapperDeleted,
                     int32 /* object_id */)