PPAPI: Fix destructor ordering problem for main-thread message loop

ppapi/proxy/ppb_message_loop_proxy.cc

 // Copyright (c) 2012 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 "ppapi/proxy/ppb_message_loop_proxy.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/compiler_specific.h"
@@ skipping 27 matching lines @@
     : MessageLoopShared(for_main_thread),
       nested_invocations_(0),
       destroyed_(false),
       should_destroy_(false),
       is_main_thread_loop_(true) {
   // We attach the main thread immediately. We can't use AttachToCurrentThread,
   // because the MessageLoop already exists.
 
   // This must be called only once, so the slot must be empty.
   CHECK(!PluginGlobals::Get()->msg_loop_slot());
-  base::ThreadLocalStorage::Slot* slot =
-      new base::ThreadLocalStorage::Slot(&ReleaseMessageLoop);
+  // We don't add a reference for TLS here, so we don't release it. Instead,
+  // this loop is owned by PluginGlobals. Contrast with AttachToCurrentThread
+  // where we register ReleaseMessageLoop with TLS and call AddRef.
+  base::ThreadLocalStorage::Slot* slot = new base::ThreadLocalStorage::Slot();
   PluginGlobals::Get()->set_msg_loop_slot(slot);
 
-  // Take a ref to the MessageLoop on behalf of the TLS. Note that this is an
-  // internal ref and not a plugin ref so the plugin can't accidentally
-  // release it. This is released by ReleaseMessageLoop().
-  AddRef();
   slot->Set(this);
 
   loop_proxy_ = base::MessageLoopProxy::current();
 }
 
 
 MessageLoopResource::~MessageLoopResource() {
 }
 
 PPB_MessageLoop_API* MessageLoopResource::AsPPB_MessageLoop_API() {
@@ skipping 199 matching lines @@
 PPB_MessageLoop_Proxy::~PPB_MessageLoop_Proxy() {
 }
 
 // static
 const PPB_MessageLoop_1_0* PPB_MessageLoop_Proxy::GetInterface() {
   return &ppb_message_loop_interface;
 }
 
 }  // namespace proxy
 }  // namespace ppapi