Formalize a RenderFrameHost::AddMessageToConsole() API.

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 81 matching lines @@
 // WebKit-level transport.
 IPC_MESSAGE_ROUTED1(DevToolsAgentMsg_DispatchOnInspectorBackend,
                     std::string /* message */)
 
 // Inspect element with the given coordinates.
 IPC_MESSAGE_ROUTED3(DevToolsAgentMsg_InspectElement,
                     std::string /* host_id */,
                     int /* x */,
                     int /* y */)
 
-// Add message to the devtools console.
-IPC_MESSAGE_ROUTED2(DevToolsAgentMsg_AddMessageToConsole,
-                    content::ConsoleMessageLevel /* level */,
-                    std::string /* message */)
-
 //-----------------------------------------------------------------------------
 // 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_ROUTED0(DevToolsMsg_SetupDevToolsClient)
 
 
 //-----------------------------------------------------------------------------
 // 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 */)