[DevTools] Support multiple sessions in Target domain

content/browser/devtools/protocol/target_handler.h

Index: content/browser/devtools/protocol/target_handler.h
diff --git a/content/browser/devtools/protocol/target_handler.h b/content/browser/devtools/protocol/target_handler.h
index 6a0b02c649f95d93a509de7c98940fa8e6e0a47d..c7e29c9b104a72ea3b3ffcc56d5882295dd53855 100644
--- a/content/browser/devtools/protocol/target_handler.h
+++ b/content/browser/devtools/protocol/target_handler.h
@@ -11,7 +11,6 @@
 #include "content/browser/devtools/protocol/devtools_domain_handler.h"
 #include "content/browser/devtools/protocol/target.h"
 #include "content/browser/devtools/service_worker_devtools_manager.h"
-#include "content/public/browser/devtools_agent_host_client.h"
 #include "content/public/browser/devtools_agent_host_observer.h"
 
 namespace content {
@@ -23,7 +22,6 @@ namespace protocol {
 
 class TargetHandler : public DevToolsDomainHandler,
                       public Target::Backend,
-                      public DevToolsAgentHostClient,
                       public ServiceWorkerDevToolsManager::Observer,
                       public DevToolsAgentHostObserver {
  public:
@@ -47,9 +45,9 @@ class TargetHandler : public DevToolsDomainHandler,
   Response SetRemoteLocations(
       std::unique_ptr<protocol::Array<Target::RemoteLocation>>) override;
   Response AttachToTarget(const std::string& target_id,
-                          bool* out_success) override;
-  Response DetachFromTarget(const std::string& target_id) override;
-  Response SendMessageToTarget(const std::string& target_id,
+                          Maybe<std::string>* out_session_id) override;
+  Response DetachFromTarget(const std::string& session_id) override;
+  Response SendMessageToTarget(const std::string& session_id,
                                const std::string& message) override;
   Response GetTargetInfo(
       const std::string& target_id,
@@ -79,9 +77,11 @@ class TargetHandler : public DevToolsDomainHandler,
                              bool waiting_for_debugger);
   void TargetCreatedInternal(DevToolsAgentHost* host);
   void TargetDestroyedInternal(DevToolsAgentHost* host);
-  bool AttachToTargetInternal(DevToolsAgentHost* host,
-                              bool waiting_for_debugger);
-  void DetachFromTargetInternal(DevToolsAgentHost* host);
+  std::string AttachToTargetInternal(DevToolsAgentHost* host,
+                                     bool waiting_for_debugger,
+                                     bool is_auto_attach);
+  bool DetachFromSessionInternal(const std::string& session_id);
+  bool IsAttachedToAgentHost(DevToolsAgentHost* agent_host);
 
   // ServiceWorkerDevToolsManager::Observer implementation.
   void WorkerCreated(ServiceWorkerDevToolsAgentHost* host) override;
@@ -97,11 +97,7 @@ class TargetHandler : public DevToolsDomainHandler,
   void DevToolsAgentHostAttached(DevToolsAgentHost* agent_host) override;
   void DevToolsAgentHostDetached(DevToolsAgentHost* agent_host) override;
 
-  // DevToolsAgentHostClient implementation.
-  void DispatchProtocolMessage(DevToolsAgentHost* agent_host,
-                               const std::string& message) override;
-  void AgentHostClosed(DevToolsAgentHost* agent_host,
-                       bool replaced_with_another_client) override;
+  class Session;
 
   std::unique_ptr<Target::Frontend> frontend_;
   bool discover_;
@@ -109,9 +105,11 @@ class TargetHandler : public DevToolsDomainHandler,
   bool wait_for_debugger_on_start_;
   bool attach_to_frames_;
   RenderFrameHostImpl* render_frame_host_;
-  HostsMap attached_hosts_;
+  std::map<std::string, std::unique_ptr<Session>> attached_sessions_;
+  HostsMap auto_attached_hosts_;

[caseq, 2017/06/27 18:29:30]

Does this have to be a map -- i.e. can it be a set<DevToolsAgentHost> instead?

   std::set<GURL> frame_urls_;
   RawHostsMap reported_hosts_;
+  int last_session_id_ = 0;
 
   DISALLOW_COPY_AND_ASSIGN(TargetHandler);
 };