Introduce EmbeddedWorkerDevToolsAgent.

content/common/service_worker/embedded_worker_messages.h

Index: content/common/service_worker/embedded_worker_messages.h
diff --git a/content/common/service_worker/embedded_worker_messages.h b/content/common/service_worker/embedded_worker_messages.h
index 5631cd92862ca307ca2c55e67708e52fc3fdc5a9..f7d330816d6bfaa3688dbc4e045499392082101e 100644
--- a/content/common/service_worker/embedded_worker_messages.h
+++ b/content/common/service_worker/embedded_worker_messages.h
@@ -38,6 +38,10 @@ IPC_MESSAGE_CONTROL4(EmbeddedWorkerMsg_StartWorker,
 IPC_MESSAGE_CONTROL1(EmbeddedWorkerMsg_StopWorker,
                      int /* embedded_worker_id */)
 
+IPC_MESSAGE_CONTROL2(EmbeddedWorkerMsg_MessageToWorker,

[kinuko, 2014/04/28 07:25:56]

If this message type's only used to dispatch devtools messages can we reflect
that to its name (and comment)?  We also have similar message
EmbeddedWorkerContextMsg_MessageToWorker and it's probably too confusing.

[horo, 2014/04/28 08:33:09]

Done.

+                     int /* embedded_worker_id */,
+                     IPC::Message /* message */)
+
 // Renderer -> Browser message to indicate that the worker is started.
 IPC_MESSAGE_CONTROL2(EmbeddedWorkerHostMsg_WorkerStarted,
                      int /* thread_id */,