[DevTools] Rework DevToolsSession interaction with domain handlers.

content/browser/devtools/protocol/tracing_handler.cc

 // Copyright 2014 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.
 
 #include "content/browser/devtools/protocol/tracing_handler.h"
 
 #include <cmath>
 
 #include "base/bind.h"
 #include "base/format_macros.h"
@@ skipping 100 matching lines @@
 
   scoped_refptr<DevToolsIOContext::Stream> stream_;
   base::WeakPtr<TracingHandler> tracing_handler_;
 };
 
 }  // namespace
 
 TracingHandler::TracingHandler(TracingHandler::Target target,
                                int frame_tree_node_id,
                                DevToolsIOContext* io_context)
-    : target_(target),
+    : DevToolsDomainHandler(Tracing::Metainfo::domainName),
+      target_(target),
       io_context_(io_context),
       frame_tree_node_id_(frame_tree_node_id),
       did_initiate_recording_(false),
       return_as_stream_(false),
       weak_factory_(this) {}
 
 TracingHandler::~TracingHandler() {
 }
 
 void TracingHandler::Wire(UberDispatcher* dispatcher) {
   frontend_.reset(new Tracing::Frontend(dispatcher->channel()));
   Tracing::Dispatcher::wire(dispatcher, this);
 }
 
+void TracingHandler::SetRenderFrameHost(RenderFrameHostImpl* host) {
+}
+
 Response TracingHandler::Disable() {
   if (did_initiate_recording_)
     StopTracing(scoped_refptr<TracingController::TraceDataSink>());
   return Response::OK();
 }
 
 void TracingHandler::OnTraceDataCollected(const std::string& trace_fragment) {
   // Hand-craft protocol notification message so we can substitute JSON
   // that we already got as string as a bare object, not a quoted string.
   std::string message(
@@ skipping 205 matching lines @@
 
   std::string mode;
   if (tracing_dict->GetString(kRecordModeParam, &mode))
     tracing_dict->SetString(kRecordModeParam, ConvertFromCamelCase(mode, '-'));
 
   return base::trace_event::TraceConfig(*tracing_dict);
 }
 
 }  // namespace tracing
 }  // namespace protocol