DevTools: Never instantiate DevToolsAgentHost on threads other than UI

chrome/browser/extensions/api/debugger/debugger_api.cc

 // Copyright (c) 2012 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.
 
 // Implements the Chrome Extensions Debugger API.
 
 #include "chrome/browser/extensions/api/debugger/debugger_api.h"
 
 #include <map>
 #include <set>
@@ skipping 743 matching lines @@
 
   std::vector<RenderViewHost*> rvh_list =
       DevToolsAgentHost::GetValidRenderViewHosts();
   for (std::vector<RenderViewHost*>::iterator it = rvh_list.begin();
        it != rvh_list.end(); ++it) {
     base::Value* value = SerializePageInfo(*it);
     if (value)
       results_list->Append(value);
   }
 
-  content::BrowserThread::PostTaskAndReply(
+  content::BrowserThread::PostTaskAndReplyWithResult(
       content::BrowserThread::IO,
       FROM_HERE,
-      base::Bind(&DebuggerGetTargetsFunction::CollectWorkerInfo, this,
-                 results_list),
+      base::Bind(&DebuggerGetTargetsFunction::CollectWorkerInfo, this),
       base::Bind(&DebuggerGetTargetsFunction::SendTargetList, this,
                  results_list));
   return true;
 }
 
-void DebuggerGetTargetsFunction::CollectWorkerInfo(base::ListValue* list) {
-  std::vector<WorkerService::WorkerInfo> worker_info =
-      WorkerService::GetInstance()->GetWorkers();
+DebuggerGetTargetsFunction::WorkerInfoList
+DebuggerGetTargetsFunction::CollectWorkerInfo() {
+  return WorkerService::GetInstance()->GetWorkers();
+}
+
+void DebuggerGetTargetsFunction::SendTargetList(
+    base::ListValue* list,
+    const WorkerInfoList& worker_info) {
   for (size_t i = 0; i < worker_info.size(); ++i)
     list->Append(SerializeWorkerInfo(worker_info[i]));
-}
-
-void DebuggerGetTargetsFunction::SendTargetList(base::ListValue* list) {
   SetResult(list);
   SendResponse(true);
 }