DevTools: use explicit IPC messages for enabling/disabling tracing instead of intercepting protocol…

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 96 matching lines @@
 
 // Transport from Inspector frontend to frontend host.
 IPC_MESSAGE_ROUTED1(DevToolsHostMsg_DispatchOnEmbedder,
                     std::string /* message */)
 
 // Updates agent runtime state stored in devtools manager in order to support
 // cross-navigation instrumentation.
 IPC_MESSAGE_ROUTED1(DevToolsHostMsg_SaveAgentRuntimeState,
                     std::string /* state */)
 
+// Tells the host to enable trace event recording.
+IPC_MESSAGE_ROUTED1(DevToolsHostMsg_EnableTracing,
+                    std::string /* category_filter */)
+
+// Tells the host to disable trace event recording.
+IPC_MESSAGE_ROUTED0(DevToolsHostMsg_DisableTracing)
+
 //-----------------------------------------------------------------------------
 // These are messages sent from the GPU process to the inspected renderer.
 
 IPC_STRUCT_BEGIN(GpuTaskInfo)
   IPC_STRUCT_MEMBER(double, timestamp)
   IPC_STRUCT_MEMBER(int, phase)
   IPC_STRUCT_MEMBER(bool, foreign)
   IPC_STRUCT_MEMBER(uint64, gpu_memory_used_bytes)
   IPC_STRUCT_MEMBER(uint64, gpu_memory_limit_bytes)
 IPC_STRUCT_END()
 
 // Recorded events are passed in chunks to the renderer process.
 IPC_MESSAGE_ROUTED1(DevToolsAgentMsg_GpuTasksChunk,
                     std::vector<GpuTaskInfo> /* gpu_tasks */)
 
 //-----------------------------------------------------------------------------
 // These are messages sent from the inspected page renderer to the worker
 // renderer.