[DevTools] Support multiple sessions in content/ domain handlers

content/browser/devtools/protocol/tracing_handler.h

 // 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.
 
 #ifndef CONTENT_BROWSER_DEVTOOLS_PROTOCOL_TRACING_HANDLER_H_
 #define CONTENT_BROWSER_DEVTOOLS_PROTOCOL_TRACING_HANDLER_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <set>
 #include <string>
 
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/trace_event/trace_event.h"
 #include "content/browser/devtools/protocol/devtools_domain_handler.h"
 #include "content/browser/devtools/protocol/tracing.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/tracing_controller.h"
 
 namespace base {
 class Timer;
 }
 
 namespace content {
 
+class DevToolsAgentHostImpl;
 class DevToolsIOContext;
-class DevToolsSession;
 
 namespace protocol {
 
 class TracingHandler : public DevToolsDomainHandler,
                        public Tracing::Backend {
  public:
   enum Target { Browser, Renderer };
   TracingHandler(Target target,
                  int frame_tree_node_id,
                  DevToolsIOContext* io_context);
   ~TracingHandler() override;
 
-  static TracingHandler* FromSession(DevToolsSession* session);
+  static std::vector<TracingHandler*> ForAgentHost(DevToolsAgentHostImpl* host);
 
   void Wire(UberDispatcher* dispatcher) override;
   Response Disable() override;
 
   void OnTraceDataCollected(const std::string& trace_fragment);
   void OnTraceComplete();
   void OnTraceToStreamComplete(const std::string& stream_handle);
 
   // Protocol methods.
   void Start(Maybe<std::string> categories,
@@ skipping 40 matching lines @@
 
   FRIEND_TEST_ALL_PREFIXES(TracingHandlerTest,
                            GetTraceConfigFromDevToolsConfig);
   DISALLOW_COPY_AND_ASSIGN(TracingHandler);
 };
 
 }  // namespace protocol
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DEVTOOLS_PROTOCOL_TRACING_HANDLER_H_