[DevTools] filter any messages from previous session in DevToolsAgentHostImpl

content/common/devtools_messages.h

 // Copyright (c) 2012 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.
 
 // Developer tools consist of the following parts:
 //
 // DevToolsAgent lives in the renderer of an inspected page and provides access
 // to the pages resources, DOM, v8 etc. by means of IPC messages.
 //
 // DevToolsClient is a thin delegate that lives in the tools front-end
@@ skipping 40 matching lines @@
 #define IPC_MESSAGE_EXPORT CONTENT_EXPORT
 
 #define IPC_MESSAGE_START DevToolsMsgStart
 
 // These are messages sent from DevToolsAgent to DevToolsClient through the
 // browser.
 
 // Agent -> Client message chunk.
 //   |is_first| marks the first chunk, comes with the |message_size| for
 //   total message size.
-//   |is_last| marks the last chunk. |call_id| and |post_state| are optional
-//    parameters passed with the last chunk of the protocol response.
+//   |is_last| marks the last chunk. |call_id|, |session_id| and |post_state|
+//   are optional parameters passed with the last chunk of the protocol
+//   response.
 IPC_STRUCT_BEGIN(DevToolsMessageChunk)
   IPC_STRUCT_MEMBER(bool, is_first)
   IPC_STRUCT_MEMBER(bool, is_last)
   IPC_STRUCT_MEMBER(int, message_size)
+  IPC_STRUCT_MEMBER(int, session_id)
   IPC_STRUCT_MEMBER(int, call_id)
   IPC_STRUCT_MEMBER(std::string, data)
   IPC_STRUCT_MEMBER(std::string, post_state)
 IPC_STRUCT_END()
 
 // Sends response from the agent to the client. Supports chunked encoding.
 IPC_MESSAGE_ROUTED1(DevToolsClientMsg_DispatchOnInspectorFrontend,
                     DevToolsMessageChunk /* message */)
 
 //-----------------------------------------------------------------------------
 // These are messages sent from DevToolsClient to DevToolsAgent through the
 // browser.
 // Tells agent that there is a client host connected to it.
-IPC_MESSAGE_ROUTED1(DevToolsAgentMsg_Attach,
-                    std::string /* host_id */)
+IPC_MESSAGE_ROUTED2(DevToolsAgentMsg_Attach,
+                    std::string /* host_id */,
+                    int /* session_id */)
 
 // Tells agent that a client host was disconnected from another agent and
 // connected to this one.
-IPC_MESSAGE_ROUTED2(DevToolsAgentMsg_Reattach,
+IPC_MESSAGE_ROUTED3(DevToolsAgentMsg_Reattach,
                     std::string /* host_id */,
+                    int /* session_id */,
                     std::string /* agent_state */)
 
 // Tells agent that there is no longer a client host connected to it.
 IPC_MESSAGE_ROUTED0(DevToolsAgentMsg_Detach)
 
 // WebKit-level transport.
-IPC_MESSAGE_ROUTED1(DevToolsAgentMsg_DispatchOnInspectorBackend,
+IPC_MESSAGE_ROUTED2(DevToolsAgentMsg_DispatchOnInspectorBackend,
+                    int /* session_id */,
                     std::string /* message */)
 
 // Inspect element with the given coordinates.
-IPC_MESSAGE_ROUTED3(DevToolsAgentMsg_InspectElement,
+IPC_MESSAGE_ROUTED4(DevToolsAgentMsg_InspectElement,
                     std::string /* host_id */,
+                    int /* session_id */,
                     int /* x */,
                     int /* y */)
 
 //-----------------------------------------------------------------------------
 // These are messages sent from the browser to the renderer.
 
 // RenderViewHostDelegate::RenderViewCreated method sends this message to a
 // new renderer to notify it that it will host developer tools UI and should
 // set up all neccessary bindings and create DevToolsClient instance that
 // will handle communication with inspected page DevToolsAgent.
 IPC_MESSAGE_ROUTED1(DevToolsMsg_SetupDevToolsClient,
                     std::string /* compatibility script */)
 
 
 //-----------------------------------------------------------------------------
 // These are messages sent from the renderer to the browser.
 
 // Transport from Inspector frontend to frontend host.
 IPC_MESSAGE_ROUTED1(DevToolsHostMsg_DispatchOnEmbedder,
                     std::string /* message */)