Revert 212948 "Made MessagePump a non-thread safe class."

trunk/src/base/message_loop/message_loop_proxy_impl.cc

Index: trunk/src/base/message_loop/message_loop_proxy_impl.cc
===================================================================
--- trunk/src/base/message_loop/message_loop_proxy_impl.cc	(revision 212951)
+++ trunk/src/base/message_loop/message_loop_proxy_impl.cc	(working copy)
@@ -5,44 +5,82 @@
 #include "base/message_loop/message_loop_proxy_impl.h"
 
 #include "base/location.h"
-#include "base/logging.h"
-#include "base/message_loop/incoming_task_queue.h"
-#include "base/message_loop/message_loop.h"
+#include "base/threading/thread_restrictions.h"
 
 namespace base {
-namespace internal {
 
-MessageLoopProxyImpl::MessageLoopProxyImpl(
-    scoped_refptr<IncomingTaskQueue> incoming_queue)
-    : incoming_queue_(incoming_queue),
-      valid_thread_id_(PlatformThread::CurrentId()) {
+MessageLoopProxyImpl::~MessageLoopProxyImpl() {
 }
 
 bool MessageLoopProxyImpl::PostDelayedTask(
     const tracked_objects::Location& from_here,
     const base::Closure& task,
     base::TimeDelta delay) {
-  DCHECK(!task.is_null()) << from_here.ToString();
-  return incoming_queue_->AddToIncomingQueue(from_here, task, delay, true);
+  return PostTaskHelper(from_here, task, delay, true);
 }
 
 bool MessageLoopProxyImpl::PostNonNestableDelayedTask(
     const tracked_objects::Location& from_here,
     const base::Closure& task,
     base::TimeDelta delay) {
-  DCHECK(!task.is_null()) << from_here.ToString();
-  return incoming_queue_->AddToIncomingQueue(from_here, task, delay, false);
+  return PostTaskHelper(from_here, task, delay, false);
 }
 
 bool MessageLoopProxyImpl::RunsTasksOnCurrentThread() const {
-  return valid_thread_id_ == PlatformThread::CurrentId();
+  // We shouldn't use MessageLoop::current() since it uses LazyInstance which
+  // may be deleted by ~AtExitManager when a WorkerPool thread calls this
+  // function.
+  // http://crbug.com/63678
+  base::ThreadRestrictions::ScopedAllowSingleton allow_singleton;
+  AutoLock lock(message_loop_lock_);
+  return (target_message_loop_ &&
+          (MessageLoop::current() == target_message_loop_));
 }
 
-MessageLoopProxyImpl::~MessageLoopProxyImpl() {
+// MessageLoop::DestructionObserver implementation
+void MessageLoopProxyImpl::WillDestroyCurrentMessageLoop() {
+  AutoLock lock(message_loop_lock_);
+  target_message_loop_ = NULL;
 }
 
-}  // namespace internal
+void MessageLoopProxyImpl::OnDestruct() const {
+  // We shouldn't use MessageLoop::current() since it uses LazyInstance which
+  // may be deleted by ~AtExitManager when a WorkerPool thread calls this
+  // function.
+  // http://crbug.com/63678
+  base::ThreadRestrictions::ScopedAllowSingleton allow_singleton;
+  bool delete_later = false;
+  {
+    AutoLock lock(message_loop_lock_);
+    if (target_message_loop_ &&
+        (MessageLoop::current() != target_message_loop_)) {
+      target_message_loop_->DeleteSoon(FROM_HERE, this);
+      delete_later = true;
+    }
+  }
+  if (!delete_later)
+    delete this;
+}
 
+MessageLoopProxyImpl::MessageLoopProxyImpl()
+    : target_message_loop_(MessageLoop::current()) {
+}
+
+bool MessageLoopProxyImpl::PostTaskHelper(
+    const tracked_objects::Location& from_here, const base::Closure& task,
+    base::TimeDelta delay, bool nestable) {
+  AutoLock lock(message_loop_lock_);
+  if (target_message_loop_) {
+    if (nestable) {
+      target_message_loop_->PostDelayedTask(from_here, task, delay);
+    } else {
+      target_message_loop_->PostNonNestableDelayedTask(from_here, task, delay);
+    }
+    return true;
+  }
+  return false;
+}
+
 scoped_refptr<MessageLoopProxy>
 MessageLoopProxy::current() {
   MessageLoop* cur_loop = MessageLoop::current();