[DevTools] Support multiple sessions in content/ 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 113 matching lines @@
       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() {
 }
 
 // static
-TracingHandler* TracingHandler::FromSession(DevToolsSession* session) {
-  return static_cast<TracingHandler*>(
-      session->GetHandlerByName(Tracing::Metainfo::domainName));
+std::vector<TracingHandler*> TracingHandler::ForAgentHost(
+    DevToolsAgentHostImpl* host) {
+  return DevToolsSession::HandlersForAgentHost<TracingHandler>(
+      host, Tracing::Metainfo::domainName);
 }
 
 void TracingHandler::Wire(UberDispatcher* dispatcher) {
   frontend_.reset(new Tracing::Frontend(dispatcher->channel()));
   Tracing::Dispatcher::wire(dispatcher, this);
 }
 
 Response TracingHandler::Disable() {
   if (did_initiate_recording_)
     StopTracing(scoped_refptr<TracingController::TraceDataSink>());
@@ skipping 212 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