Make much of the proxy thread-safe with 1 great big lock.

ppapi/proxy/plugin_resource_tracker.cc

 // Copyright (c) 2011 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/plugin_resource_tracker.h"
 
 #include "base/logging.h"
 #include "base/memory/singleton.h"
 #include "ppapi/proxy/plugin_dispatcher.h"
 #include "ppapi/proxy/ppapi_messages.h"
 #include "ppapi/proxy/serialized_var.h"
+#include "ppapi/shared_impl/proxy_lock.h"
 #include "ppapi/shared_impl/resource.h"
 #include "ppapi/shared_impl/tracker_base.h"
 #include "ppapi/shared_impl/var.h"
 
 namespace ppapi {
 namespace proxy {
 
 namespace {
 
 // When non-NULL, this object overrides the ResourceTrackerSingleton.
 PluginResourceTracker* g_resource_tracker_override = NULL;
 
 TrackerBase* GetTrackerBase() {
   return PluginResourceTracker::GetInstance();
 }
 
 }  // namespace
 
 PluginResourceTracker::PluginResourceTracker()
     : var_tracker_test_override_(NULL) {
+#ifdef ENABLE_PEPPER_THREADING
+  // Set the global proxy lock, since the plugin-side of the proxy needs to be
+  // synchronized.
+  ppapi::ProxyLock::Set(&proxy_lock_);
+#endif
 }
 
 PluginResourceTracker::~PluginResourceTracker() {
+#ifdef ENABLE_PEPPER_THREADING
+  ppapi::ProxyLock::Reset();
+#endif
 }
 
 // static
 void PluginResourceTracker::SetInstanceForTest(PluginResourceTracker* tracker) {
   g_resource_tracker_override = tracker;
 }
 
 // static
 PluginResourceTracker* PluginResourceTracker::GetInstance() {
   if (g_resource_tracker_override)
@@ skipping 61 matching lines @@
       // the instance was destroyed. In that case the browser-side resource has
       // already been freed correctly on the browser side.
       dispatcher->Send(new PpapiHostMsg_PPBCore_ReleaseResource(
           INTERFACE_ID_PPB_CORE, object->host_resource()));
     }
   }
 }
 
 }  // namespace proxy
 }  // namespace ppapi