PPAPI: Don't use MessageLoop::current in the plugin process

ppapi/proxy/ppb_instance_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_instance_proxy.h"
 
 #include "base/memory/ref_counted.h"
 #include "base/stl_util.h"
 #include "build/build_config.h"
 #include "media/base/limits.h"
@@ skipping 911 matching lines @@
   //
   // Be careful to post a task to avoid reentering the plugin.
 
   InstanceData* data =
       static_cast<PluginDispatcher*>(dispatcher())->GetInstanceData(instance);
   if (!data)
     return;
   data->should_do_request_surrounding_text = true;
 
   if (!data->is_request_surrounding_text_pending) {
-    base::MessageLoop::current()->PostTask(
+    PpapiGlobals::Get()->GetMainThreadMessageLoop()->PostTask(
         FROM_HERE,
         RunWhileLocked(base::Bind(&RequestSurroundingText, instance)));
     data->is_request_surrounding_text_pending = true;
   }
 }
 
 void PPB_Instance_Proxy::UpdateSurroundingText(PP_Instance instance,
                                                const char* text,
                                                uint32_t caret,
                                                uint32_t anchor) {
@@ skipping 568 matching lines @@
     PP_Instance instance) {
   InstanceData* data = static_cast<PluginDispatcher*>(dispatcher())->
       GetInstanceData(instance);
   if (!data)
     return;  // Instance was probably deleted.
   data->should_do_request_surrounding_text = false;
 }
 
 }  // namespace proxy
 }  // namespace ppapi