Update //base to chromium 9659b08ea5a34f889dc4166217f438095ddc10d2

base/message_loop/message_loop.cc

Index: base/message_loop/message_loop.cc
diff --git a/base/message_loop/message_loop.cc b/base/message_loop/message_loop.cc
index 4222c774dd58b20354d6b0e4c948efcbbf5abf1b..6bd6730cde34752a3e7db50ee8d2f153379013da 100644
--- a/base/message_loop/message_loop.cc
+++ b/base/message_loop/message_loop.cc
@@ -19,6 +19,7 @@
 #include "base/thread_task_runner_handle.h"
 #include "base/threading/thread_local.h"
 #include "base/time/time.h"
+#include "base/trace_event/trace_event.h"
 #include "base/tracked_objects.h"
 
 #if defined(OS_MACOSX)
@@ -170,7 +171,8 @@ MessageLoop::~MessageLoop() {
   // Tell the incoming queue that we are dying.
   incoming_task_queue_->WillDestroyCurrentMessageLoop();
   incoming_task_queue_ = NULL;
-  message_loop_proxy_ = NULL;
+  unbound_task_runner_ = NULL;
+  task_runner_ = NULL;
 
   // OK, now make it so that no one can find us.
   lazy_tls_ptr.Pointer()->Set(NULL);
@@ -257,27 +259,27 @@ void MessageLoop::RemoveDestructionObserver(
 void MessageLoop::PostTask(
     const tracked_objects::Location& from_here,
     const Closure& task) {
-  message_loop_proxy_->PostTask(from_here, task);
+  task_runner_->PostTask(from_here, task);
 }
 
 void MessageLoop::PostDelayedTask(
     const tracked_objects::Location& from_here,
     const Closure& task,
     TimeDelta delay) {
-  message_loop_proxy_->PostDelayedTask(from_here, task, delay);
+  task_runner_->PostDelayedTask(from_here, task, delay);
 }
 
 void MessageLoop::PostNonNestableTask(
     const tracked_objects::Location& from_here,
     const Closure& task) {
-  message_loop_proxy_->PostNonNestableTask(from_here, task);
+  task_runner_->PostNonNestableTask(from_here, task);
 }
 
 void MessageLoop::PostNonNestableDelayedTask(
     const tracked_objects::Location& from_here,
     const Closure& task,
     TimeDelta delay) {
-  message_loop_proxy_->PostNonNestableDelayedTask(from_here, task, delay);
+  task_runner_->PostNonNestableDelayedTask(from_here, task, delay);
 }
 
 void MessageLoop::Run() {
@@ -367,6 +369,7 @@ bool MessageLoop::IsIdleForTesting() {
 
 //------------------------------------------------------------------------------
 
+// static
 scoped_ptr<MessageLoop> MessageLoop::CreateUnbound(
     Type type, MessagePumpFactoryCallback pump_factory) {
   return make_scoped_ptr(new MessageLoop(type, pump_factory));
@@ -386,8 +389,9 @@ MessageLoop::MessageLoop(Type type, MessagePumpFactoryCallback pump_factory)
       message_histogram_(NULL),
       run_loop_(NULL),
       incoming_task_queue_(new internal::IncomingTaskQueue(this)),
-      message_loop_proxy_(
-          new internal::MessageLoopProxyImpl(incoming_task_queue_)) {
+      unbound_task_runner_(
+          new internal::MessageLoopTaskRunner(incoming_task_queue_)),
+      task_runner_(unbound_task_runner_) {
   // If type is TYPE_CUSTOM non-null pump_factory must be given.
   DCHECK_EQ(type_ == TYPE_CUSTOM, !pump_factory_.is_null());
 }
@@ -403,9 +407,26 @@ void MessageLoop::BindToCurrentThread() {
   lazy_tls_ptr.Pointer()->Set(this);
 
   incoming_task_queue_->StartScheduling();
-  message_loop_proxy_->BindToCurrentThread();
-  thread_task_runner_handle_.reset(
-      new ThreadTaskRunnerHandle(message_loop_proxy_));
+  unbound_task_runner_->BindToCurrentThread();
+  unbound_task_runner_ = nullptr;
+  SetThreadTaskRunnerHandle();
+}
+
+void MessageLoop::SetTaskRunner(
+    scoped_refptr<SingleThreadTaskRunner> task_runner) {
+  DCHECK_EQ(this, current());
+  DCHECK(task_runner->BelongsToCurrentThread());
+  DCHECK(!unbound_task_runner_);
+  task_runner_ = task_runner.Pass();
+  SetThreadTaskRunnerHandle();
+}
+
+void MessageLoop::SetThreadTaskRunnerHandle() {
+  DCHECK_EQ(this, current());
+  // Clear the previous thread task runner first because only one can exist at
+  // a time.
+  thread_task_runner_handle_.reset();
+  thread_task_runner_handle_.reset(new ThreadTaskRunnerHandle(task_runner_));
 }
 
 void MessageLoop::RunHandler() {
@@ -453,10 +474,11 @@ void MessageLoop::RunTask(const PendingTask& pending_task) {
 
   HistogramEvent(kTaskRunEvent);
 
+  TRACE_TASK_EXECUTION("toplevel", pending_task);
+
   FOR_EACH_OBSERVER(TaskObserver, task_observers_,
                     WillProcessTask(pending_task));
-  task_annotator_.RunTask(
-      "MessageLoop::PostTask", "MessageLoop::RunTask", pending_task);
+  task_annotator_.RunTask("MessageLoop::PostTask", pending_task);
   FOR_EACH_OBSERVER(TaskObserver, task_observers_,
                     DidProcessTask(pending_task));