Add trace code to track all posted tasks in message_loop.

base/message_loop.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/message_loop.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
 #include "base/debug/alias.h"
+#include "base/debug/trace_event.h"
 #include "base/lazy_instance.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop_proxy_impl.h"
 #include "base/message_pump_default.h"
 #include "base/metrics/histogram.h"
 #include "base/third_party/dynamic_annotations/dynamic_annotations.h"
 #include "base/threading/thread_local.h"
 #include "base/time.h"
 #include "base/tracked_objects.h"
@@ skipping 429 matching lines @@
     return false;
 
   PendingTask pending_task = deferred_non_nestable_work_queue_.front();
   deferred_non_nestable_work_queue_.pop();
 
   RunTask(pending_task);
   return true;
 }
 
 void MessageLoop::RunTask(const PendingTask& pending_task) {
+  UNSHIPPED_TRACE_EVENT2("task", "MessageLoop::RunTask",
+                         "src_file", pending_task.posted_from.file_name(),
+                         "src_func", pending_task.posted_from.function_name());
   DCHECK(nestable_tasks_allowed_);
   // Execute the task and assume the worst: It is probably not reentrant.
   nestable_tasks_allowed_ = false;
 
   // Before running the task, store the program counter where it was posted
   // and deliberately alias it to ensure it is on the stack if the task
   // crashes. Be careful not to assume that the variable itself will have the
   // expected value when displayed by the optimizer in an optimized build.
   // Look at a memory dump of the stack.
-  const void* program_counter = pending_task.birth_program_counter;
+  const void* program_counter =
+      pending_task.posted_from.program_counter();
   base::debug::Alias(&program_counter);
 
   HistogramEvent(kTaskRunEvent);
   FOR_EACH_OBSERVER(TaskObserver, task_observers_,
                     WillProcessTask(pending_task.time_posted));
   pending_task.task.Run();
   FOR_EACH_OBSERVER(TaskObserver, task_observers_,
                     DidProcessTask(pending_task.time_posted));
 
 #if defined(TRACK_ALL_TASK_OBJECTS)
@@ skipping 277 matching lines @@
 // MessageLoop::PendingTask
 
 MessageLoop::PendingTask::PendingTask(
     const base::Closure& task,
     const tracked_objects::Location& posted_from,
     TimeTicks delayed_run_time,
     bool nestable)
     : task(task),
       time_posted(TimeTicks::Now()),
       delayed_run_time(delayed_run_time),
+      posted_from(posted_from),
       sequence_num(0),
-      nestable(nestable),
-      birth_program_counter(posted_from.program_counter()) {
+      nestable(nestable) {
 #if defined(TRACK_ALL_TASK_OBJECTS)
   post_births = tracked_objects::ThreadData::TallyABirthIfActive(posted_from);
 #endif  // defined(TRACK_ALL_TASK_OBJECTS)
 }
 
 MessageLoop::PendingTask::~PendingTask() {
 }
 
 bool MessageLoop::PendingTask::operator<(const PendingTask& other) const {
   // Since the top of a priority queue is defined as the "greatest" element, we
@@ skipping 65 matching lines @@
                                            Watcher *delegate) {
   return pump_libevent()->WatchFileDescriptor(
       fd,
       persistent,
       static_cast<base::MessagePumpLibevent::Mode>(mode),
       controller,
       delegate);
 }
 
 #endif