Add trace code to track all posted tasks in message_loop.

base/threading/worker_pool_win.cc

 // Copyright (c) 2011 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 "base/threading/worker_pool.h"
 
 #include "base/bind.h"
+#include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/task.h"
 #include "base/tracked_objects.h"
 
 namespace base {
 
 namespace {
 
 struct PendingTask {
   PendingTask(
       const tracked_objects::Location& posted_from,
       const base::Closure& task)
-      : task(task) {
+      : posted_from(posted_from),
+        task(task) {
 #if defined(TRACK_ALL_TASK_OBJECTS)
     post_births = tracked_objects::ThreadData::TallyABirthIfActive(posted_from);
     time_posted = TimeTicks::Now();
 #endif  // defined(TRACK_ALL_TASK_OBJECTS)
   }
 
 #if defined(TRACK_ALL_TASK_OBJECTS)
   // Counter for location where the Closure was posted from.
   tracked_objects::Births* post_births;
 
   // Time the task was posted.
   TimeTicks time_posted;
 #endif  // defined(TRACK_ALL_TASK_OBJECTS)
 
+  // The site this PendingTask was posted from.
+  tracked_objects::Location posted_from;
+
   // The task to run.
   base::Closure task;
 };
 
 DWORD CALLBACK WorkItemCallback(void* param) {
   PendingTask* pending_task = static_cast<PendingTask*>(param);
+  UNSHIPPED_TRACE_EVENT2("task", "WorkItemCallback::Run",
+                         "src_file", pending_task->posted_from.file_name(),
+                         "src_func", pending_task->posted_from.function_name());
   pending_task->task.Run();
 #if defined(TRACK_ALL_TASK_OBJECTS)
   tracked_objects::ThreadData::TallyADeathIfActive(
       pending_task->post_births,
       TimeTicks::Now() - pending_task->time_posted);
 #endif  // defined(TRACK_ALL_TASK_OBJECTS)
   delete pending_task;
   return 0;
 }
 
@@ skipping 23 matching lines @@
   return PostTaskInternal(pending_task, task_is_slow);
 }
 
 bool WorkerPool::PostTask(const tracked_objects::Location& from_here,
                           const base::Closure& task, bool task_is_slow) {
   PendingTask* pending_task = new PendingTask(from_here, task);
   return PostTaskInternal(pending_task, task_is_slow);
 }
 
 }  // namespace base