--- a/ipc/chromium/src/base/message_loop.cc
+++ b/ipc/chromium/src/base/message_loop.cc
@@ -402,16 +402,25 @@ void MessageLoop::ReloadWorkQueue() {
     if (incoming_queue_.empty())
       return;
     std::swap(incoming_queue_, work_queue_);
     DCHECK(incoming_queue_.empty());
   }
 }
 
 bool MessageLoop::DeletePendingTasks() {
+#ifdef DEBUG
+  if (!work_queue_.empty()) {
+    Task* task = work_queue_.front().task;
+    tracked_objects::Location loc = task->GetBirthPlace();
+    printf("Unexpected task! %s:%s:%d\n",
+	   loc.function_name(), loc.file_name(), loc.line_number());
+  }
+#endif
+
   MOZ_ASSERT(work_queue_.empty());
   bool did_work = !deferred_non_nestable_work_queue_.empty();
   while (!deferred_non_nestable_work_queue_.empty()) {
     Task* task = deferred_non_nestable_work_queue_.front().task;
     deferred_non_nestable_work_queue_.pop();
     delete task;
   }
   did_work |= !delayed_work_queue_.empty();

--- a/ipc/chromium/src/base/tracked.cc
+++ b/ipc/chromium/src/base/tracked.cc
@@ -76,16 +76,23 @@ void Tracked::SetBirthPlace(const Locati
     tracked_births_->ForgetBirth();
   ThreadData* current_thread_data = ThreadData::current();
   if (!current_thread_data)
     return;  // Shutdown started, and this thread wasn't registered.
   tracked_births_ = current_thread_data->FindLifetime(from_here);
   tracked_births_->RecordBirth();
 }
 
+Location Tracked::GetBirthPlace() const {
+  if (tracked_births_) {
+    return tracked_births_->location();
+  }
+  return Location();
+}
+
 void Tracked::ResetBirthTime() {
   tracked_birth_time_ = Time::Now();
 }
 
 bool Tracked::MissingBirthplace() const {
   return -1 == tracked_births_->location().line_number();
 }
 

--- a/ipc/chromium/src/base/tracked.h
+++ b/ipc/chromium/src/base/tracked.h
@@ -94,16 +94,17 @@ class Births;
 
 class Tracked {
  public:
   Tracked();
   virtual ~Tracked();
 
   // Used to record the FROM_HERE location of a caller.
   void SetBirthPlace(const Location& from_here);
+  Location GetBirthPlace() const;
 
   // When a task sits around a long time, such as in a timer, or object watcher,
   // this method should be called when the task becomes active, and its
   // significant lifetime begins (and its waiting to be woken up has passed).
   void ResetBirthTime();
 
   bool MissingBirthplace() const;