PPAPI: Make blocking completion callbacks work.

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"
 #include "base/message_loop.h"
 #include "ppapi/c/dev/ppb_message_loop_dev.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/proxy/plugin_dispatcher.h"
 #include "ppapi/proxy/plugin_globals.h"
+#include "ppapi/shared_impl/proxy_lock.h"
 #include "ppapi/shared_impl/resource.h"
 #include "ppapi/thunk/enter.h"
 #include "ppapi/thunk/ppb_message_loop_api.h"
 
 using ppapi::thunk::PPB_MessageLoop_API;
 
 namespace ppapi {
 namespace proxy {
 
 namespace {
@@ skipping 107 matching lines @@
   return PP_OK;
 }
 
 int32_t MessageLoopResource::Run() {
   if (!IsCurrent())
     return PP_ERROR_WRONG_THREAD;
   // TODO(brettw) prevent this from happening on the main thread & return
   // PP_ERROR_BLOCKS_MAIN_THREAD.  Maybe have a special constructor for that
   // one?
 
-  // TODO(brettw) figure out how to release the lock. Can't run the message
-  // loop while holding the lock.
   nested_invocations_++;
-  loop_->Run();
+  CallWhileUnlocked(base::Bind(&MessageLoop::Run,
+                               base::Unretained(loop_.get())));
   nested_invocations_--;
 
   if (should_destroy_ && nested_invocations_ == 0) {
     loop_.reset();
     destroyed_ = true;
   }
   return PP_OK;
 }
 
 int32_t MessageLoopResource::PostWork(PP_CompletionCallback callback,
@@ skipping 133 matching lines @@
 PPB_MessageLoop_Proxy::~PPB_MessageLoop_Proxy() {
 }
 
 // static
 const PPB_MessageLoop_Dev_0_1* PPB_MessageLoop_Proxy::GetInterface() {
   return &ppb_message_loop_interface;
 }
 
 }  // namespace proxy
 }  // namespace ppapi