DevTools: introduce Target.attachToBrowserTarget for flattened operation.

Change-Id: I1ddb0f06353aa88673cb690dfb35d82f8b4559ac
Reviewed-on: https://chromium-review.googlesource.com/1136895
Commit-Queue: Pavel Feldman <pfeldman@chromium.org>
Reviewed-by: Dmitry Gozman <dgozman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#575147}

content/browser/devtools/browser_devtools_agent_host.cc

@@ -52,17 +52,18 @@ BrowserDevToolsAgentHost::~BrowserDevToolsAgentHost() {
 
 bool BrowserDevToolsAgentHost::AttachSession(DevToolsSession* session,
                                              TargetRegistry* parent_registry) {
-  DCHECK(!parent_registry);
-
   if (session->restricted())
     return false;
 
-  auto registry = std::make_unique<TargetRegistry>(session);
-  TargetRegistry* registry_ptr = registry.get();
-  target_registries_[session->client()] = std::move(registry);
+  TargetRegistry* registry = parent_registry;
+  if (!registry) {
+    auto new_registry = std::make_unique<TargetRegistry>(session);
+    registry = new_registry.get();
+    target_registries_[session->client()] = std::move(new_registry);
+  }
   session->SetBrowserOnly(true);
   session->AddHandler(std::make_unique<protocol::TargetHandler>(
-      true /* browser_only */, GetId(), registry_ptr));
+      true /* browser_only */, GetId(), registry));
   if (only_discovery_)
     return true;
 
@@ -111,9 +112,11 @@ bool BrowserDevToolsAgentHost::DispatchProtocolMessage(
     DevToolsAgentHostClient* client,
     const std::string& message,
     base::DictionaryValue* parsed_message) {
-  auto* target_registry = target_registries_[client].get();
-  if (target_registry->DispatchMessageOnAgentHost(message, parsed_message))
+  auto it = target_registries_.find(client);
+  if (it != target_registries_.end() &&
+      it->second->DispatchMessageOnAgentHost(message, parsed_message)) {
     return true;
+  }
   return DevToolsAgentHostImpl::DispatchProtocolMessage(client, message,
                                                         parsed_message);
 }

content/browser/devtools/protocol/target_handler.cc

@@ -547,6 +547,14 @@ Response TargetHandler::AttachToTarget(const std::string& target_id,
   return Response::OK();
 }
 
+Response TargetHandler::AttachToBrowserTarget(std::string* out_session_id) {
+  scoped_refptr<DevToolsAgentHost> agent_host =
+      DevToolsAgentHost::CreateForBrowser(
+          nullptr, DevToolsAgentHost::CreateServerSocketCallback());
+  *out_session_id = Session::Attach(this, agent_host.get(), false, true);
+  return Response::OK();
+}
+
 Response TargetHandler::DetachFromTarget(Maybe<std::string> session_id,
                                          Maybe<std::string> target_id) {
   Session* session = nullptr;

content/browser/devtools/protocol/target_handler.h

@@ -55,6 +55,7 @@ class TargetHandler : public DevToolsDomainHandler,
   Response AttachToTarget(const std::string& target_id,
                           Maybe<bool> flatten,
                           std::string* out_session_id) override;
+  Response AttachToBrowserTarget(std::string* out_session_id) override;
   Response DetachFromTarget(Maybe<std::string> session_id,
                             Maybe<std::string> target_id) override;
   Response SendMessageToTarget(const std::string& message,

third_party/blink/renderer/core/inspector/browser_protocol.pdl

@@ -5796,6 +5796,12 @@ domain Target
       # Id assigned to the session.
       SessionID sessionId
 
+  # Attaches to the browser target, only uses flat sessionId mode.
+  experimental command attachToBrowserTarget
+    returns
+      # Id assigned to the session.
+      SessionID sessionId
+
   # Closes the target. If the target is a page that gets closed too.
   command closeTarget
     parameters