Fix a race condition in the Java Bridge when adding objects

content/common/java_bridge_messages.h

Index: content/common/java_bridge_messages.h
diff --git a/content/common/java_bridge_messages.h b/content/common/java_bridge_messages.h
index 4329f719ec8ea35e7af493a5d562e1cf1b05791e..ef412e81422fdb049b421628a10c8c1bae8e15ca 100644
--- a/content/common/java_bridge_messages.h
+++ b/content/common/java_bridge_messages.h
@@ -15,8 +15,7 @@
 // Messages for handling Java objects injected into JavaScript -----------------
 
 // Sent from browser to renderer to initialize the Java Bridge.
-IPC_MESSAGE_ROUTED1(JavaBridgeMsg_Init,
-                    IPC::ChannelHandle) /* channel handle */
+IPC_MESSAGE_ROUTED0(JavaBridgeMsg_Init)
 
 // Sent from browser to renderer to add a Java object with the given name.
 IPC_MESSAGE_ROUTED2(JavaBridgeMsg_AddNamedObject,
@@ -26,3 +25,7 @@ IPC_MESSAGE_ROUTED2(JavaBridgeMsg_AddNamedObject,
 // Sent from browser to renderer to remove a Java object with the given name.
 IPC_MESSAGE_ROUTED1(JavaBridgeMsg_RemoveNamedObject,
                     string16 /* name */)
+
+// Sent from renderer to browser to get the channel handle for NP channel.
+IPC_SYNC_MESSAGE_ROUTED0_1(JavaBridgeHostMsg_GetChannelHandle,
+                           IPC::ChannelHandle) /* channel handle */