Fix race condition in utility process clients

content/browser/plugin_loader_posix.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 "content/browser/plugin_loader_posix.h"
 
 #include "base/bind.h"
 #include "base/message_loop.h"
 #include "base/message_loop_proxy.h"
 #include "base/metrics/histogram.h"
 #include "content/common/child_process_host_impl.h"
 #include "content/common/utility_messages.h"
 #include "content/public/browser/browser_thread.h"
 #include "webkit/plugins/npapi/plugin_list.h"
 
 using content::BrowserThread;
 using content::ChildProcessHost;
 
 PluginLoaderPosix::PluginLoaderPosix()
-    : process_host_(NULL),
-      next_load_index_(0) {
+    : next_load_index_(0) {
 }
 
 void PluginLoaderPosix::LoadPlugins(
     scoped_refptr<base::MessageLoopProxy> target_loop,
     const content::PluginService::GetPluginsCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   callbacks_.push_back(PendingCallback(target_loop, callback));
 
   if (callbacks_.size() == 1) {
@@ skipping 14 matching lines @@
 
 void PluginLoaderPosix::OnProcessCrashed(int exit_code) {
   canonical_list_.erase(canonical_list_.begin(),
                         canonical_list_.begin() + next_load_index_ + 1);
   next_load_index_ = 0;
 
   LoadPluginsInternal();
 }
 
 bool PluginLoaderPosix::Send(IPC::Message* message) {
-  return process_host_->Send(message);
+  if (process_host_)
+    return process_host_->Send(message);
+  return false;
 }
 
 PluginLoaderPosix::~PluginLoaderPosix() {
 }
 
 void PluginLoaderPosix::GetPluginsToLoad() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
 
   base::TimeTicks start_time(base::TimeTicks::Now());
 
@@ skipping 21 matching lines @@
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
 
   // Check if the list is empty or all plugins have already been loaded before
   // forking.
   if (MaybeRunPendingCallbacks())
     return;
 
   if (load_start_time_.is_null())
     load_start_time_ = base::TimeTicks::Now();
 
-  process_host_ = new UtilityProcessHost(this, BrowserThread::IO);
+  process_host_ =
+      (new UtilityProcessHost(this, BrowserThread::IO))->AsWeakPtr();
   process_host_->set_no_sandbox(true);
 #if defined(OS_MACOSX)
   process_host_->set_child_flags(ChildProcessHost::CHILD_ALLOW_HEAP_EXECUTION);
 #endif
 
   process_host_->Send(new UtilityMsg_LoadPlugins(canonical_list_));
 }
 
 void PluginLoaderPosix::OnPluginLoaded(uint32 index,
                                        const webkit::WebPluginInfo& plugin) {
@@ skipping 63 matching lines @@
 
 PluginLoaderPosix::PendingCallback::PendingCallback(
     scoped_refptr<base::MessageLoopProxy> loop,
     const content::PluginService::GetPluginsCallback& cb)
     : target_loop(loop),
       callback(cb) {
 }
 
 PluginLoaderPosix::PendingCallback::~PendingCallback() {
 }