DevTools: allow embedder handling async remote debugger commands.

content/browser/devtools/devtools_session.cc

 // Copyright 2016 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/devtools_session.h"
 
 #include "base/json/json_reader.h"
 #include "base/json/json_writer.h"
 #include "content/browser/devtools/devtools_agent_host_impl.h"
 #include "content/browser/devtools/devtools_manager.h"
 #include "content/browser/devtools/protocol/protocol.h"
 #include "content/public/browser/devtools_manager_delegate.h"
 
 namespace content {
 
-DevToolsSession::DevToolsSession(
-    DevToolsAgentHostImpl* agent_host,
-    DevToolsAgentHostClient* client,
-    int session_id)
+DevToolsSession::DevToolsSession(DevToolsAgentHostImpl* agent_host,
+                                 DevToolsAgentHostClient* client,
+                                 int session_id)
     : agent_host_(agent_host),
       client_(client),
       session_id_(session_id),
       host_(nullptr),
-      dispatcher_(new protocol::UberDispatcher(this)) {
-}
+      dispatcher_(new protocol::UberDispatcher(this)),
+      weak_factory_(this) {}
 
 DevToolsSession::~DevToolsSession() {
   dispatcher_.reset();
   for (auto& pair : handlers_)
     pair.second->Disable();
   handlers_.clear();
 }
 
 void DevToolsSession::AddHandler(
     std::unique_ptr<protocol::DevToolsDomainHandler> handler) {
   handler->Wire(dispatcher_.get());
   handler->SetRenderFrameHost(host_);
   handlers_[handler->name()] = std::move(handler);
 }
 
 void DevToolsSession::SetRenderFrameHost(RenderFrameHostImpl* host) {
   host_ = host;
   for (auto& pair : handlers_)
     pair.second->SetRenderFrameHost(host_);
 }
 
 void DevToolsSession::SetFallThroughForNotFound(bool value) {
   dispatcher_->setFallThroughForNotFound(value);
 }
 
+void DevToolsSession::sendResponse(
+    std::unique_ptr<base::DictionaryValue> response) {
+  std::string json;
+  base::JSONWriter::Write(*response.get(), &json);
+  agent_host_->SendMessageToClient(session_id_, json);
+}
+
 protocol::Response::Status DevToolsSession::Dispatch(
     const std::string& message,
     int* call_id,
     std::string* method) {
   std::unique_ptr<base::Value> value = base::JSONReader::Read(message);
 
   DevToolsManagerDelegate* delegate =
       DevToolsManager::GetInstance()->delegate();
   if (value && value->IsType(base::Value::Type::DICTIONARY) && delegate) {
     std::unique_ptr<base::DictionaryValue> response(delegate->HandleCommand(
         agent_host_,
         static_cast<base::DictionaryValue*>(value.get())));

[pfeldman, 2017/02/21 19:10:24]

nit: extract variable.

     if (response) {
-      std::string json;
-      base::JSONWriter::Write(*response.get(), &json);
-      agent_host_->SendMessageToClient(session_id_, json);
+      sendResponse(std::move(response));
       return protocol::Response::kSuccess;
     }
+    if (delegate->HandleAsyncCommand(
+            agent_host_, static_cast<base::DictionaryValue*>(value.get()),
+            base::Bind(&DevToolsSession::sendResponse,
+                       weak_factory_.GetWeakPtr()))) {
+      return protocol::Response::kAsync;
+    }
   }
 
   return dispatcher_->dispatch(protocol::toProtocolValue(value.get(), 1000),
                                call_id, method);
 }
 
 void DevToolsSession::sendProtocolResponse(
     int call_id,
     std::unique_ptr<protocol::Serializable> message) {
   agent_host_->SendMessageToClient(session_id_, message->serialize());
 }
 
 void DevToolsSession::sendProtocolNotification(
     std::unique_ptr<protocol::Serializable> message) {
   agent_host_->SendMessageToClient(session_id_, message->serialize());
 }
 
 void DevToolsSession::flushProtocolNotifications() {
 }
 
 protocol::DevToolsDomainHandler* DevToolsSession::GetHandlerByName(
     const std::string& name) {
   auto it = handlers_.find(name);
   if (it == handlers_.end())
     return nullptr;
   return it->second.get();
 }
 
 }  // namespace content