Refactor plugin process code which checks with the browser process before shutdown, to avoid races in which the browser process thinks the process is fine to use while it's shutting down. I also removed PluginProcess/WorkerProcess since they didn't have any code in them now.

I removed the plugin process code which waits 10 seconds before shutting itself down.  That was a premature optimization, since testing with/without this didn't show any difference (see http://www/~jabdelmalek/chrome/test/plugins/processes.html).  In both cases, the plugin on a page would get recreated in less than 100ms, even with reusing or starting a plugin process from scratch.  We already spawn new renderer processes on back and forth if it's a different origin, and the plugin will be in the cache anyways.


Review URL: http://codereview.chromium.org/53091

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@12703 0039d316-1c4b-4281-b951-d872f2087c98

31 files changed, 116 insertions, 335 deletions

diff --git a/chrome/browser/browser_shutdown.cc b/chrome/browser/browser_shutdown.cc
index 40e470f..23aa42d 100644
--- a/chrome/browser/browser_shutdown.cc
+++ b/chrome/browser/browser_shutdown.cc
@@ -16,7 +16,6 @@
 #include "chrome/browser/first_run.h"
 #include "chrome/browser/jankometer.h"
 #include "chrome/browser/metrics/metrics_service.h"
-#include "chrome/browser/plugin_service.h"
 #include "chrome/browser/renderer_host/render_process_host.h"
 #include "chrome/browser/renderer_host/render_view_host.h"
 #include "chrome/browser/renderer_host/render_widget_host.h"
@@ -106,11 +105,6 @@ void Shutdown() {
   // Notifies we are going away.
   g_browser_process->shutdown_event()->Signal();
 
-  PluginService* plugin_service = PluginService::GetInstance();
-  if (plugin_service) {
-    plugin_service->Shutdown();
-  }
-
   PrefService* prefs = g_browser_process->local_state();
 
   chrome_browser_net::SaveHostNamesForNextStartup(prefs);
diff --git a/chrome/browser/plugin_process_host.cc b/chrome/browser/plugin_process_host.cc
index e7a7f30..5031a35 100644
--- a/chrome/browser/plugin_process_host.cc
+++ b/chrome/browser/plugin_process_host.cc
@@ -505,8 +505,6 @@ void PluginProcessHost::OnMessageReceived(const IPC::Message& msg) {
     IPC_MESSAGE_HANDLER(PluginProcessHostMsg_DownloadUrl, OnDownloadUrl)
     IPC_MESSAGE_HANDLER(PluginProcessHostMsg_GetPluginFinderUrl,
                         OnGetPluginFinderUrl)
-    IPC_MESSAGE_HANDLER(PluginProcessHostMsg_ShutdownRequest,
-                        OnPluginShutdownRequest)
     IPC_MESSAGE_HANDLER(PluginProcessHostMsg_PluginMessage, OnPluginMessage)
     IPC_MESSAGE_HANDLER(PluginProcessHostMsg_GetCookies, OnGetCookies)
     IPC_MESSAGE_HANDLER_DELAY_REPLY(PluginProcessHostMsg_ResolveProxy,
@@ -657,21 +655,6 @@ void PluginProcessHost::OnGetPluginFinderUrl(std::string* plugin_finder_url) {
   *plugin_finder_url = kDefaultPluginFinderURL;
 }
 
-void PluginProcessHost::OnPluginShutdownRequest() {
-#if defined(OS_WIN)
-  DCHECK(MessageLoop::current() ==
-         ChromeThread::GetMessageLoop(ChromeThread::IO));
-
-  // If we have pending channel open requests from the renderers, then
-  // refuse the shutdown request from the plugin process.
-  bool ok_to_shutdown = sent_requests_.empty();
-  Send(new PluginProcessMsg_ShutdownResponse(ok_to_shutdown));
-#else
-  // TODO(port): Port plugin_messages_internal.h.
-  NOTIMPLEMENTED();
-#endif
-}
-
 void PluginProcessHost::OnPluginMessage(
     const std::vector<uint8>& data) {
   DCHECK(MessageLoop::current() ==
@@ -684,12 +667,3 @@ void PluginProcessHost::OnPluginMessage(
     chrome_plugin->functions().on_message(data_ptr, data_len);
   }
 }
-
-void PluginProcessHost::Shutdown() {
-#if defined(OS_WIN)
-  Send(new PluginProcessMsg_BrowserShutdown);
-#else
-  // TODO(port): Port plugin_messages_internal.h.
-  NOTIMPLEMENTED();
-#endif
-}
diff --git a/chrome/browser/plugin_process_host.h b/chrome/browser/plugin_process_host.h
index bc15ca2..71b7c77 100644
--- a/chrome/browser/plugin_process_host.h
+++ b/chrome/browser/plugin_process_host.h
@@ -75,9 +75,6 @@ class PluginProcessHost : public ChildProcessHost,
   void OnModalDialogResponse(const std::string& json_retval,
                              IPC::Message* sync_result);
 
-  // Shuts down the current plugin process instance.
-  void Shutdown();
-
   const WebPluginInfo& info() const { return info_; }
 
 #if defined(OS_WIN)
@@ -106,7 +103,6 @@ class PluginProcessHost : public ChildProcessHost,
   void OnGetCookies(uint32 request_context, const GURL& url,
                     std::string* cookies);
   void OnResolveProxy(const GURL& url, IPC::Message* reply_msg);
-  void OnPluginShutdownRequest();
   void OnPluginMessage(const std::vector<uint8>& data);
 
 #if defined(OS_WIN)
@@ -114,6 +110,8 @@ class PluginProcessHost : public ChildProcessHost,
   void OnDestroyWindow(HWND window);
 #endif
 
+  virtual bool CanShutdown() { return sent_requests_.empty(); }
+
   struct ChannelRequest {
     ChannelRequest(ResourceMessageFilter* renderer_message_filter,
                    const std::string& m, IPC::Message* r) :
diff --git a/chrome/browser/plugin_service.cc b/chrome/browser/plugin_service.cc
index 26f791b..d46a1d5 100644
--- a/chrome/browser/plugin_service.cc
+++ b/chrome/browser/plugin_service.cc
@@ -27,8 +27,7 @@ PluginService* PluginService::GetInstance() {
 PluginService::PluginService()
     : main_message_loop_(MessageLoop::current()),
       resource_dispatcher_host_(NULL),
-      ui_locale_(g_browser_process->GetApplicationLocale()),
-      plugin_shutdown_handler_(new ShutdownHandler) {
+      ui_locale_(g_browser_process->GetApplicationLocale()) {
   // Have the NPAPI plugin list search for Chrome plugins as well.
   ChromePluginLib::RegisterPluginsWithNPAPI();
   // Load the one specified on the command line as well.
@@ -172,27 +171,3 @@ bool PluginService::HavePluginFor(const std::string& mime_type,
                                                        allow_wildcard, &info,
                                                        NULL);
 }
-
-void PluginService::Shutdown() {
-  plugin_shutdown_handler_->InitiateShutdown();
-}
-
-void PluginService::OnShutdown() {
-  for (ChildProcessHost::Iterator iter(ChildProcessInfo::PLUGIN_PROCESS);
-       !iter.Done(); ++iter) {
-    static_cast<PluginProcessHost*>(*iter)->Shutdown();
-  }
-}
-
-void PluginService::ShutdownHandler::InitiateShutdown() {
-  g_browser_process->io_thread()->message_loop()->PostTask(
-      FROM_HERE,
-      NewRunnableMethod(this, &ShutdownHandler::OnShutdown));
-}
-
-void PluginService::ShutdownHandler::OnShutdown() {
-  PluginService* plugin_service = PluginService::GetInstance();
-  if (plugin_service) {
-    plugin_service->OnShutdown();
-  }
-}
diff --git a/chrome/browser/plugin_service.h b/chrome/browser/plugin_service.h
index d4f9368..d193cda 100644
--- a/chrome/browser/plugin_service.h
+++ b/chrome/browser/plugin_service.h
@@ -101,10 +101,6 @@ class PluginService {
     return resource_dispatcher_host_;
   }
 
-  // Initiates shutdown on all running PluginProcessHost instances.
-  // Can be invoked on the main thread.
-  void Shutdown();
-
  private:
   friend struct DefaultSingletonTraits<PluginService>;
 
@@ -113,9 +109,6 @@ class PluginService {
   PluginService();
   ~PluginService();
 
-  // Shutdown handler which executes in the context of the IO thread.
-  void OnShutdown();
-
   // mapping between plugin path and PluginProcessHost
   typedef base::hash_map<FilePath, PluginProcessHost*> PluginMap;
   PluginMap plugin_hosts_;
@@ -136,26 +129,6 @@ class PluginService {
   // webkit_glue since this class is called on the main and IO thread.
   Lock lock_;
 
-  // Handles plugin process shutdown.
-  class ShutdownHandler : public base::RefCountedThreadSafe<ShutdownHandler> {
-   public:
-     ShutdownHandler() {}
-     ~ShutdownHandler() {}
-
-     // Initiates plugin process shutdown. Ensures that the actual shutdown
-     // happens on the io thread.
-     void InitiateShutdown();
-
-   private:
-    // Shutdown handler which runs on the io thread.
-    void OnShutdown();
-
-    DISALLOW_COPY_AND_ASSIGN(ShutdownHandler);
-  };
-
-  friend class ShutdownHandler;
-  scoped_refptr<ShutdownHandler> plugin_shutdown_handler_;
-
   DISALLOW_COPY_AND_ASSIGN(PluginService);
 };
 
diff --git a/chrome/browser/worker_host/worker_process_host.h b/chrome/browser/worker_host/worker_process_host.h
index 0a885ea..cf8072c 100644
--- a/chrome/browser/worker_host/worker_process_host.h
+++ b/chrome/browser/worker_host/worker_process_host.h
@@ -44,6 +44,8 @@ class WorkerProcessHost : public ChildProcessHost {
   // Called when a message arrives from the worker process.
   void OnMessageReceived(const IPC::Message& message);
 
+  virtual bool CanShutdown() { return instances_.empty(); }
+
   // Updates the title shown in the task manager.
   void UpdateTitle();
 
diff --git a/chrome/chrome.gyp b/chrome/chrome.gyp
index f4c431e..3f1b847 100644
--- a/chrome/chrome.gyp
+++ b/chrome/chrome.gyp
@@ -2702,8 +2702,6 @@
             'plugin/plugin_channel_base.cc',
             'plugin/plugin_channel_base.h',
             'plugin/plugin_main.cc',
-            'plugin/plugin_process.cc',
-            'plugin/plugin_process.h',
             'plugin/plugin_thread.cc',
             'plugin/plugin_thread.h',
             'plugin/webplugin_delegate_stub.cc',
@@ -2740,8 +2738,6 @@
             'worker/webworkerclient_proxy.cc',
             'worker/webworkerclient_proxy.h',
             'worker/worker_main.cc',
-            'worker/worker_process.cc',
-            'worker/worker_process.h',
             'worker/worker_thread.cc',
             'worker/worker_thread.h',
             'worker/worker_webkitclient_impl.cc',
diff --git a/chrome/common/child_process.cc b/chrome/common/child_process.cc
index 27b55b7..55f5bb0 100644
--- a/chrome/common/child_process.cc
+++ b/chrome/common/child_process.cc
@@ -35,32 +35,22 @@ ChildProcess::~ChildProcess() {
   child_process_ = NULL;
 }
 
-// Called on any thread
 void ChildProcess::AddRefProcess() {
-  base::AtomicRefCountInc(&ref_count_);
+  DCHECK(MessageLoop::current() == child_thread_->message_loop());
+  ref_count_++;
 }
 
-// Called on any thread
 void ChildProcess::ReleaseProcess() {
-  DCHECK(!base::AtomicRefCountIsZero(&ref_count_));
+  DCHECK(MessageLoop::current() == child_thread_->message_loop());
+  DCHECK(ref_count_);
   DCHECK(child_process_);
-  if (!base::AtomicRefCountDec(&ref_count_))
-    child_process_->OnFinalRelease();
+  if (--ref_count_)
+    return;
+
+  child_thread_->OnProcessFinalRelease();
 }
 
 base::WaitableEvent* ChildProcess::GetShutDownEvent() {
   DCHECK(child_process_);
   return &child_process_->shutdown_event_;
 }
-
-// Called on any thread
-bool ChildProcess::ProcessRefCountIsZero() {
-  return base::AtomicRefCountIsZero(&ref_count_);
-}
-
-void ChildProcess::OnFinalRelease() {
-  if (child_thread_.get()) {
-    child_thread_->owner_loop()->PostTask(
-        FROM_HERE, new MessageLoop::QuitTask());
-  }
-}
diff --git a/chrome/common/child_process.h b/chrome/common/child_process.h
index 5844b5b..23bfad8 100644
--- a/chrome/common/child_process.h
+++ b/chrome/common/child_process.h
@@ -7,7 +7,6 @@
 
 #include <string>
 #include <vector>
-#include "base/atomic_ref_count.h"
 #include "base/basictypes.h"
 #include "base/message_loop.h"
 #include "base/scoped_ptr.h"
@@ -40,34 +39,21 @@ class ChildProcess {
   base::WaitableEvent* GetShutDownEvent();
 
   // These are used for ref-counting the child process.  The process shuts
-  // itself down when the ref count reaches 0.  These functions may be called
-  // on any thread.
+  // itself down when the ref count reaches 0.
   // For example, in the renderer process, generally each tab managed by this
   // process will hold a reference to the process, and release when closed.
   void AddRefProcess();
   void ReleaseProcess();
 
- protected:
-  friend class ChildThread;
-
   // Getter for the one ChildProcess object for this process.
   static ChildProcess* current() { return child_process_; }
 
- protected:
-  bool ProcessRefCountIsZero();
-
-  // Derived classes can override this to alter the behavior when the ref count
-  // reaches 0. The default implementation calls Quit on the main message loop
-  // which causes the process to shutdown. Note, this can be called on any
-  // thread. (See ReleaseProcess)
-  virtual void OnFinalRelease();
-
  private:
   // NOTE: make sure that child_thread_ is listed before shutdown_event_, since
   // it depends on it (indirectly through IPC::SyncChannel).
   scoped_ptr<ChildThread> child_thread_;
 
-  base::AtomicRefCount ref_count_;
+  int ref_count_;
 
   // An event that will be signalled when we shutdown.
   base::WaitableEvent shutdown_event_;
diff --git a/chrome/common/child_process_host.cc b/chrome/common/child_process_host.cc
index 4269678..6618554 100644
--- a/chrome/common/child_process_host.cc
+++ b/chrome/common/child_process_host.cc
@@ -17,7 +17,12 @@
 #include "chrome/common/process_watcher.h"
 #include "chrome/common/result_codes.h"
 
-typedef std::list<ChildProcessInfo*> ChildProcessList;
+#if defined(OS_WIN)
+#include "chrome/common/plugin_messages.h"
+#endif
+
+namespace {
+typedef std::list<ChildProcessHost*> ChildProcessList;
 
 // The NotificationTask is used to notify about plugin process connection/
 // disconnection. It is needed because the notifications in the
@@ -39,6 +44,9 @@ class ChildNotificationTask : public Task {
   ChildProcessInfo info_;
 };
 
+}  // namespace
+
+
 
 ChildProcessHost::ChildProcessHost(
     ProcessType type, ResourceDispatcherHost* resource_dispatcher_host)
@@ -143,10 +151,22 @@ void ChildProcessHost::ListenerHook::OnMessageReceived(
   bool msg_is_ok = true;
   bool handled = host_->resource_dispatcher_host_->OnMessageReceived(
       msg, host_, &msg_is_ok);
-  if (!handled)
-    host_->OnMessageReceived(msg);
 
-  if (!msg_is_ok) 
+  if (!handled) {
+#if defined(OS_WIN)
+    if (msg.type() == PluginProcessHostMsg_ShutdownRequest::ID) {
+      // Must remove the process from the list now, in case it gets used for a
+      // new instance before our watcher tells us that the process terminated.
+      Singleton<ChildProcessList>::get()->remove(host_);
+      if (host_->CanShutdown())
+        host_->Send(new PluginProcessMsg_Shutdown());
+#endif
+    } else {
+      host_->OnMessageReceived(msg);
+    }
+  }
+
+  if (!msg_is_ok)
     base::KillProcess(host_->handle(), ResultCodes::KILLED_BAD_MESSAGE, false);
 
 #ifdef IPC_MESSAGE_LOG_ENABLED
@@ -158,6 +178,7 @@ void ChildProcessHost::ListenerHook::OnMessageReceived(
 void ChildProcessHost::ListenerHook::OnChannelConnected(int32 peer_pid) {
   host_->opening_channel_ = false;
   host_->OnChannelConnected(peer_pid);
+  host_->Send(new PluginProcessMsg_AskBeforeShutdown());
 
   // Notify in the main loop of the connection.
   host_->Notify(NotificationType::CHILD_PROCESS_HOST_CONNECTED);
@@ -186,7 +207,7 @@ ChildProcessHost::Iterator::Iterator(ProcessType type)
     ++(*this);
 }
 
-ChildProcessInfo* ChildProcessHost::Iterator::operator++() {
+ChildProcessHost* ChildProcessHost::Iterator::operator++() {
   do {
     ++iterator_;
     if (Done())
diff --git a/chrome/common/child_process_host.h b/chrome/common/child_process_host.h
index cef940c..d4d2dd9 100644
--- a/chrome/common/child_process_host.h
+++ b/chrome/common/child_process_host.h
@@ -38,21 +38,24 @@ class ChildProcessHost : public ResourceDispatcherHost::Receiver,
    public:
     Iterator();
     Iterator(ProcessType type);
-    ChildProcessInfo* operator->() { return *iterator_; }
-    ChildProcessInfo* operator*() { return *iterator_; }
-    ChildProcessInfo* operator++();
+    ChildProcessHost* operator->() { return *iterator_; }
+    ChildProcessHost* operator*() { return *iterator_; }
+    ChildProcessHost* operator++();
     bool Done();
 
    private:
     bool all_;
     ProcessType type_;
-    std::list<ChildProcessInfo*>::iterator iterator_;
+    std::list<ChildProcessHost*>::iterator iterator_;
   };
 
  protected:
   ChildProcessHost(ProcessType type,
                    ResourceDispatcherHost* resource_dispatcher_host);
 
+  // Derived classes return true if it's ok to shut down the child process.
+  virtual bool CanShutdown() = 0;
+
   // Creates the IPC channel.  Returns true iff it succeeded.
   bool CreateChannel();
 
diff --git a/chrome/common/child_thread.cc b/chrome/common/child_thread.cc
index 237e53c..22c82c0 100644
--- a/chrome/common/child_thread.cc
+++ b/chrome/common/child_thread.cc
@@ -11,13 +11,18 @@
 #include "chrome/common/ipc_logging.h"
 #include "webkit/glue/webkit_glue.h"
 
+#if defined(OS_WIN)
+#include "chrome/common/plugin_messages.h"
+#endif
+
 // V8 needs a 1MB stack size.
 const size_t ChildThread::kV8StackSize = 1024 * 1024;
 
 ChildThread::ChildThread(Thread::Options options)
     : Thread("Chrome_ChildThread"),
       owner_loop_(MessageLoop::current()),
-      options_(options) {
+      options_(options),
+      check_with_browser_before_shutdown_(false) {
   DCHECK(owner_loop_);
   channel_name_ = CommandLine::ForCurrentProcess()->GetSwitchValue(
       switches::kProcessChannelID);
@@ -66,6 +71,18 @@ void ChildThread::OnMessageReceived(const IPC::Message& msg) {
   if (resource_dispatcher_->OnMessageReceived(msg))
     return;
 
+#if defined(OS_WIN)
+  if (msg.type() == PluginProcessMsg_AskBeforeShutdown::ID) {
+    check_with_browser_before_shutdown_ = true;
+    return;
+  }
+
+  if (msg.type() == PluginProcessMsg_Shutdown::ID) {
+    owner_loop_->PostTask(FROM_HERE, new MessageLoop::QuitTask());
+    return;
+  }
+#endif
+
   if (msg.routing_id() == MSG_ROUTING_CONTROL) {
     OnControlMessageReceived(msg);
   } else {
@@ -97,3 +114,16 @@ void ChildThread::CleanUp() {
   channel_.reset();
   resource_dispatcher_.reset();
 }
+
+void ChildThread::OnProcessFinalRelease() {
+  if (!check_with_browser_before_shutdown_) {
+    owner_loop_->PostTask(FROM_HERE, new MessageLoop::QuitTask());
+    return;
+  }
+
+  // The child process shutdown sequence is a request response based mechanism,
+  // where we send out an initial feeler request to the child process host
+  // instance in the browser to verify if it's ok to shutdown the child process.
+  // The browser then sends back a response if it's ok to shutdown.
+  Send(new PluginProcessHostMsg_ShutdownRequest);
+}
diff --git a/chrome/common/child_thread.h b/chrome/common/child_thread.h
index c499cb5..66fcc09 100644
--- a/chrome/common/child_thread.h
+++ b/chrome/common/child_thread.h
@@ -41,6 +41,9 @@ class ChildThread : public IPC::Channel::Listener,
   // Overrides the channel name.  Used for --single-process mode.
   void SetChannelName(const std::wstring& name) { channel_name_ = name; }
 
+  // Called when the process refcount is 0.
+  void OnProcessFinalRelease();
+
  protected:
   // The required stack size if V8 runs on a thread.
   static const size_t kV8StackSize;
@@ -77,6 +80,11 @@ class ChildThread : public IPC::Channel::Listener,
   // NOTE: this object lives on the owner thread.
   scoped_ptr<ResourceDispatcher> resource_dispatcher_;
 
+  // If true, checks with the browser process before shutdown.  This avoids race
+  // conditions if the process refcount is 0 but there's an IPC message inflight
+  // that would addref it.
+  bool check_with_browser_before_shutdown_;
+
   DISALLOW_EVIL_CONSTRUCTORS(ChildThread);
 };
 
diff --git a/chrome/common/plugin_messages_internal.h b/chrome/common/plugin_messages_internal.h
index b9c7a58..61c53f0 100644
--- a/chrome/common/plugin_messages_internal.h
+++ b/chrome/common/plugin_messages_internal.h
@@ -16,15 +16,19 @@ IPC_BEGIN_MESSAGES(PluginProcess)
   IPC_MESSAGE_CONTROL1(PluginProcessMsg_CreateChannel,
                        bool /* off_the_record */)
 
-  IPC_MESSAGE_CONTROL1(PluginProcessMsg_ShutdownResponse,
-                       bool /* ok to shutdown */)
-
   // Allows a chrome plugin loaded in the browser process to send arbitrary
   // data to an instance of the same plugin loaded in a plugin process.
   IPC_MESSAGE_CONTROL1(PluginProcessMsg_PluginMessage,
                        std::vector<uint8> /* opaque data */)
 
-  IPC_MESSAGE_CONTROL0(PluginProcessMsg_BrowserShutdown)
+  // The following messages are used by all child processes, even though they
+  // are listed under PluginProcess.  It seems overkill to define ChildProcess.
+  // Tells the child process it should stop.
+  IPC_MESSAGE_CONTROL0(PluginProcessMsg_AskBeforeShutdown)
+
+  // Sent in response to PluginProcessHostMsg_ShutdownRequest to tell the child
+  // process that it's safe to shutdown.
+  IPC_MESSAGE_CONTROL0(PluginProcessMsg_Shutdown)
 
 IPC_END_MESSAGES(PluginProcess)
 
diff --git a/chrome/plugin/chrome_plugin_host.cc b/chrome/plugin/chrome_plugin_host.cc
index 8ac50f2..48f975a 100644
--- a/chrome/plugin/chrome_plugin_host.cc
+++ b/chrome/plugin/chrome_plugin_host.cc
@@ -7,12 +7,12 @@
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/message_loop.h"
+#include "chrome/common/child_process.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_plugin_lib.h"
 #include "chrome/common/chrome_plugin_util.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/plugin_messages.h"
-#include "chrome/plugin/plugin_process.h"
 #include "chrome/plugin/plugin_thread.h"
 #include "chrome/plugin/webplugin_proxy.h"
 #include "net/base/data_url.h"
@@ -255,9 +255,9 @@ void STDCALL CPB_SetKeepProcessAlive(CPID id, CPBool keep_alive) {
   if (desired_value != g_keep_process_alive) {
     g_keep_process_alive = desired_value;
     if (g_keep_process_alive)
-      PluginProcess::current()->AddRefProcess();
+      ChildProcess::current()->AddRefProcess();
     else
-      PluginProcess::current()->ReleaseProcess();
+      ChildProcess::current()->ReleaseProcess();
   }
 }
 
diff --git a/chrome/plugin/plugin.scons b/chrome/plugin/plugin.scons
index 3cf9e84..5621eeb 100644
--- a/chrome/plugin/plugin.scons
+++ b/chrome/plugin/plugin.scons
@@ -43,8 +43,6 @@ input_files = ChromeFileList([
     'plugin_channel_base.cc',
     'plugin_channel_base.h',
     'plugin_main.cc',
-    'plugin_process.cc',
-    'plugin_process.h',
     'plugin_thread.cc',
     'plugin_thread.h',
     '$CHROME_DIR/tools/build/win/precompiled$OBJSUFFIX',
@@ -69,7 +67,6 @@ if env.Bit('posix'):
       'plugin_channel.cc',
       'plugin_channel_base.cc',
       'plugin_main.cc',
-      'plugin_process.cc',
       'plugin_thread.cc',
       'webplugin_delegate_stub.cc',
       'webplugin_proxy.cc',
diff --git a/chrome/plugin/plugin.vcproj b/chrome/plugin/plugin.vcproj
index fadc40c..4fd5459 100644
--- a/chrome/plugin/plugin.vcproj
+++ b/chrome/plugin/plugin.vcproj
@@ -178,14 +178,6 @@
 			>
 		</File>
 		<File
-			RelativePath=".\plugin_process.cc"
-			>
-		</File>
-		<File
-			RelativePath=".\plugin_process.h"
-			>
-		</File>
-		<File
 			RelativePath=".\plugin_thread.cc"
 			>
 		</File>
diff --git a/chrome/plugin/plugin_channel.cc b/chrome/plugin/plugin_channel.cc
index 125054a..066bda3 100644
--- a/chrome/plugin/plugin_channel.cc
+++ b/chrome/plugin/plugin_channel.cc
@@ -6,12 +6,12 @@
 
 #include "chrome/plugin/plugin_channel.h"
 
-#include "chrome/common/plugin_messages.h"
 #include "base/command_line.h"
 #include "base/process_util.h"
 #include "base/string_util.h"
+#include "chrome/common/child_process.h"
+#include "chrome/common/plugin_messages.h"
 #include "chrome/common/chrome_switches.h"
-#include "chrome/plugin/plugin_process.h"
 #include "chrome/plugin/plugin_thread.h"
 
 PluginChannel* PluginChannel::GetPluginChannel(MessageLoop* ipc_message_loop) {
@@ -29,13 +29,13 @@ PluginChannel* PluginChannel::GetPluginChannel(MessageLoop* ipc_message_loop) {
 
 PluginChannel::PluginChannel() : in_send_(0), off_the_record_(false) {
   SendUnblockingOnlyDuringDispatch();
-  PluginProcess::current()->AddRefProcess();
+  ChildProcess::current()->AddRefProcess();
   const CommandLine* command_line = CommandLine::ForCurrentProcess();
   log_messages_ = command_line->HasSwitch(switches::kLogPluginMessages);
 }
 
 PluginChannel::~PluginChannel() {
-  PluginProcess::current()->ReleaseProcess();
+  ChildProcess::current()->ReleaseProcess();
 }
 
 bool PluginChannel::Send(IPC::Message* msg) {
diff --git a/chrome/plugin/plugin_channel_base.cc b/chrome/plugin/plugin_channel_base.cc
index 61b56d5..0e26e86 100644
--- a/chrome/plugin/plugin_channel_base.cc
+++ b/chrome/plugin/plugin_channel_base.cc
@@ -7,8 +7,8 @@
 #include "chrome/plugin/plugin_channel_base.h"
 
 #include "base/hash_tables.h"
+#include "chrome/common/child_process.h"
 #include "chrome/common/ipc_sync_message.h"
-#include "chrome/plugin/plugin_process.h"
 
 typedef base::hash_map<std::wstring, scoped_refptr<PluginChannelBase> >
     PluginChannelMap;
@@ -78,7 +78,7 @@ bool PluginChannelBase::Init(MessageLoop* ipc_message_loop,
                              bool create_pipe_now) {
   channel_.reset(new IPC::SyncChannel(
       channel_name_, mode_, this, NULL, ipc_message_loop, create_pipe_now,
-      PluginProcess::current()->GetShutDownEvent()));
+      ChildProcess::current()->GetShutDownEvent()));
   channel_valid_ = true;
   return true;
 }
diff --git a/chrome/plugin/plugin_main.cc b/chrome/plugin/plugin_main.cc
index f6808c1..fe71ea0 100644
--- a/chrome/plugin/plugin_main.cc
+++ b/chrome/plugin/plugin_main.cc
@@ -6,12 +6,13 @@
 #include "base/message_loop.h"
 #include "base/string_util.h"
 #include "base/system_monitor.h"
+#include "chrome/common/child_process.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/logging_chrome.h"
 #include "chrome/common/main_function_params.h"
 #include "chrome/common/win_util.h"
-#include "chrome/plugin/plugin_process.h"
+#include "chrome/plugin/plugin_thread.h"
 #include "chrome/test/injection_test_dll.h"
 #include "sandbox/src/sandbox.h"
 
@@ -54,7 +55,7 @@ int PluginMain(const MainFunctionParams& parameters) {
   }
 
   {
-    PluginProcess plugin_process;
+    ChildProcess plugin_process(new PluginThread());
     if (!no_sandbox && target_services) {
       target_services->LowerToken();
     }
diff --git a/chrome/plugin/plugin_process.cc b/chrome/plugin/plugin_process.cc
deleted file mode 100644
index 9d0f567..0000000
--- a/chrome/plugin/plugin_process.cc
+++ /dev/null
@@ -1,59 +0,0 @@
-// Copyright (c) 2006-2008 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 <windows.h>
-#include "chrome/plugin/plugin_process.h"
-
-#include "base/basictypes.h"
-#include "base/scoped_handle.h"
-#include "chrome/common/ipc_channel.h"
-#include "chrome/common/ipc_message_utils.h"
-#include "chrome/common/plugin_messages.h"
-#include "chrome/common/render_messages.h"
-#include "webkit/glue/webkit_glue.h"
-
-// How long to wait after there are no more plugin instances before killing the
-// process.
-static const int kProcessShutdownDelayMs = 10 * 1000;
-
-// No AddRef required when using PluginProcess with RunnableMethod.  This is
-// okay since the lifetime of the PluginProcess is always greater than the
-// lifetime of PluginThread because it's a member variable.
-template <> struct RunnableMethodTraits<PluginProcess> {
-  static void RetainCallee(PluginProcess*) {}
-  static void ReleaseCallee(PluginProcess*) {}
-};
-
-PluginProcess::PluginProcess()
-    : ChildProcess(new PluginThread()) {
-}
-
-PluginProcess::~PluginProcess() {
-}
-
-// Note: may be called on any thread
-void PluginProcess::OnFinalRelease() {
-  // We override this to have the process linger for a few seconds to
-  // better accomdate back/forth navigation. This avoids shutting down and
-  // immediately starting a new plugin process. If a new channel is
-  // opened in the interim, the current process will not be shutdown.
-  child_thread()->owner_loop()->PostDelayedTask(FROM_HERE, NewRunnableMethod(
-      this, &PluginProcess::OnProcessShutdownTimeout),
-      kProcessShutdownDelayMs);
-}
-
-void PluginProcess::OnProcessShutdownTimeout() {
-  if (ProcessRefCountIsZero()) {
-    // The plugin process shutdown sequence is a request response based
-    // mechanism, where we send out an initial feeler request to the plugin
-    // process host instance in the browser to verify if it is ok to shutdown
-    // the plugin process. The browser then sends back a response indicating
-    // whether it is ok to shutdown.
-    child_thread()->Send(new PluginProcessHostMsg_ShutdownRequest);
-  }
-}
-
-void PluginProcess::Shutdown() {
-  ChildProcess::OnFinalRelease();
-}
diff --git a/chrome/plugin/plugin_process.h b/chrome/plugin/plugin_process.h
deleted file mode 100644
index 467b46d..0000000
--- a/chrome/plugin/plugin_process.h
+++ /dev/null
@@ -1,38 +0,0 @@
-// Copyright (c) 2006-2008 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.
-
-#ifndef CHROME_PLUGIN_PLUGIN_PROCESS_H_
-#define CHROME_PLUGIN_PLUGIN_PROCESS_H_
-
-#include "base/file_path.h"
-#include "chrome/common/child_process.h"
-#include "chrome/plugin/plugin_thread.h"
-
-// Represents the plugin end of the renderer<->plugin connection. The
-// opposite end is the PluginProcessHost. This is a singleton object for
-// each plugin.
-class PluginProcess : public ChildProcess {
- public:
-  PluginProcess();
-  virtual ~PluginProcess();
-
-  // Invoked when the browser is shutdown. This ensures that the plugin
-  // process does not hang around waiting for future invocations
-  // from the browser.
-  void Shutdown();
-
-  // Returns a pointer to the PluginProcess singleton instance.
-  static PluginProcess* current() {
-    return static_cast<PluginProcess*>(ChildProcess::current());
-  }
-
- private:
-
-  virtual void OnFinalRelease();
-  void OnProcessShutdownTimeout();
-
-  DISALLOW_EVIL_CONSTRUCTORS(PluginProcess);
-};
-
-#endif  // CHROME_PLUGIN_PLUGIN_PROCESS_H_
diff --git a/chrome/plugin/plugin_thread.cc b/chrome/plugin/plugin_thread.cc
index 10172e7..9993c37 100644
--- a/chrome/plugin/plugin_thread.cc
+++ b/chrome/plugin/plugin_thread.cc
@@ -8,6 +8,7 @@
 #include "chrome/plugin/plugin_thread.h"
 
 #include "base/command_line.h"
+#include "chrome/common/child_process.h"
 #include "chrome/common/chrome_plugin_lib.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/notification_service.h"
@@ -15,7 +16,6 @@
 #include "chrome/common/render_messages.h"
 #include "chrome/plugin/chrome_plugin_host.h"
 #include "chrome/plugin/npobject_util.h"
-#include "chrome/plugin/plugin_process.h"
 #include "chrome/renderer/render_thread.h"
 #include "net/base/net_errors.h"
 #include "webkit/glue/plugins/plugin_lib.h"
@@ -40,9 +40,7 @@ PluginThread* PluginThread::current() {
 void PluginThread::OnControlMessageReceived(const IPC::Message& msg) {
   IPC_BEGIN_MESSAGE_MAP(PluginThread, msg)
     IPC_MESSAGE_HANDLER(PluginProcessMsg_CreateChannel, OnCreateChannel)
-    IPC_MESSAGE_HANDLER(PluginProcessMsg_ShutdownResponse, OnShutdownResponse)
     IPC_MESSAGE_HANDLER(PluginProcessMsg_PluginMessage, OnPluginMessage)
-    IPC_MESSAGE_HANDLER(PluginProcessMsg_BrowserShutdown, OnBrowserShutdown)
   IPC_END_MESSAGE_MAP()
 }
 
@@ -100,27 +98,18 @@ void PluginThread::OnCreateChannel(bool off_the_record) {
   Send(new PluginProcessHostMsg_ChannelCreated(channel_name));
 }
 
-void PluginThread::OnShutdownResponse(bool ok_to_shutdown) {
-  if (ok_to_shutdown)
-    PluginProcess::current()->Shutdown();
-}
-
-void PluginThread::OnBrowserShutdown() {
-  PluginProcess::current()->Shutdown();
-}
-
 void PluginThread::OnPluginMessage(const std::vector<unsigned char> &data) {
   // We Add/Release ref here to ensure that something will trigger the
   // shutdown mechanism for processes started in the absence of renderer's
   // opening a plugin channel.
-  PluginProcess::current()->AddRefProcess();
+  ChildProcess::current()->AddRefProcess();
   ChromePluginLib *chrome_plugin = ChromePluginLib::Find(plugin_path_);
   if (chrome_plugin) {
     void *data_ptr = const_cast<void*>(reinterpret_cast<const void*>(&data[0]));
     uint32 data_len = static_cast<uint32>(data.size());
     chrome_plugin->functions().on_message(data_ptr, data_len);
   }
-  PluginProcess::current()->ReleaseProcess();
+  ChildProcess::current()->ReleaseProcess();
 }
 
 namespace webkit_glue {
diff --git a/chrome/plugin/plugin_thread.h b/chrome/plugin/plugin_thread.h
index 1550d5a..9b999e2 100644
--- a/chrome/plugin/plugin_thread.h
+++ b/chrome/plugin/plugin_thread.h
@@ -30,9 +30,7 @@ class PluginThread : public ChildThread {
   virtual void CleanUp();
 
   void OnCreateChannel(bool off_the_record);
-  void OnShutdownResponse(bool ok_to_shutdown);
   void OnPluginMessage(const std::vector<uint8> &data);
-  void OnBrowserShutdown();
 
   scoped_ptr<NotificationService> notification_service_;
 
diff --git a/chrome/worker/webworkerclient_proxy.cc b/chrome/worker/webworkerclient_proxy.cc
index 6cc3d9b..33bcbc8 100644
--- a/chrome/worker/webworkerclient_proxy.cc
+++ b/chrome/worker/webworkerclient_proxy.cc
@@ -4,9 +4,9 @@
 
 #include "chrome/worker/webworkerclient_proxy.h"
 
+#include "chrome/common/child_process.h"
 #include "chrome/common/ipc_logging.h"
 #include "chrome/common/worker_messages.h"
-#include "chrome/worker/worker_process.h"
 #include "chrome/worker/worker_thread.h"
 #include "webkit/glue/webworker.h"
 
@@ -17,12 +17,12 @@ WebWorkerClientProxy::WebWorkerClientProxy(const GURL& url, int route_id)
       ALLOW_THIS_IN_INITIALIZER_LIST(impl_(WebWorker::Create(this))) {
   AddRef();
   WorkerThread::current()->AddRoute(route_id_, this);
-  WorkerProcess::current()->AddRefProcess();
+  ChildProcess::current()->AddRefProcess();
 }
 
 WebWorkerClientProxy::~WebWorkerClientProxy() {
   WorkerThread::current()->RemoveRoute(route_id_);
-  WorkerProcess::current()->ReleaseProcess();
+  ChildProcess::current()->ReleaseProcess();
 }
 
 void WebWorkerClientProxy::PostMessageToWorkerObject(const string16& message) {
diff --git a/chrome/worker/worker.scons b/chrome/worker/worker.scons
index 6b194c4..fe4aaa2 100644
--- a/chrome/worker/worker.scons
+++ b/chrome/worker/worker.scons
@@ -28,8 +28,6 @@ input_files = ChromeFileList([
     'webworkerclient_proxy.cc',
     'webworkerclient_proxy.h',
     'worker_main.cc',
-    'worker_process.cc',
-    'worker_process.h',
     'worker_thread.cc',
     'worker_thread.h',
     'worker_webkitclient_impl.cc',
@@ -48,7 +46,6 @@ if env.Bit('posix'):
   input_files.Remove(
       'webworker.cc',
       'worker_main.cc',
-      'worker_process.cc',
       'worker_thread.cc',
       'worker_webkitclient_impl.cc',
   )
diff --git a/chrome/worker/worker.vcproj b/chrome/worker/worker.vcproj
index 8adcbab..96d5aa34 100644
--- a/chrome/worker/worker.vcproj
+++ b/chrome/worker/worker.vcproj
@@ -150,14 +150,6 @@
 			>

 		</File>

 		<File

-			RelativePath=".\worker_process.cc"

-			>

-		</File>

-		<File

-			RelativePath=".\worker_process.h"

-			>

-		</File>

-		<File

 			RelativePath=".\worker_thread.cc"

 			>

 		</File>

diff --git a/chrome/worker/worker_main.cc b/chrome/worker/worker_main.cc
index 1b973c3..ad41a8b 100644
--- a/chrome/worker/worker_main.cc
+++ b/chrome/worker/worker_main.cc
@@ -6,12 +6,13 @@
 #include "base/message_loop.h"
 #include "base/string_util.h"
 #include "base/system_monitor.h"
+#include "chrome/common/child_process.h"
 #include "chrome/common/chrome_constants.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/logging_chrome.h"
 #include "chrome/common/main_function_params.h"
 #include "chrome/common/win_util.h"
-#include "chrome/worker/worker_process.h"
+#include "chrome/worker/worker_thread.h"
 
 #if defined(OS_WIN)
 #include "chrome/common/sandbox_init_wrapper.h"
@@ -30,7 +31,7 @@ int WorkerMain(const MainFunctionParams& parameters) {
   // Initialize the SystemMonitor
   base::SystemMonitor::Start();
 
-  WorkerProcess worker_process;
+  ChildProcess worker_process(new WorkerThread());
 #if defined(OS_WIN)
   sandbox::TargetServices* target_services =
       parameters.sandbox_info_.TargetServices();
diff --git a/chrome/worker/worker_process.cc b/chrome/worker/worker_process.cc
deleted file mode 100644
index 4d319e3..0000000
--- a/chrome/worker/worker_process.cc
+++ /dev/null
@@ -1,14 +0,0 @@
-// Copyright (c) 2009 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 "chrome/worker/worker_process.h"
-
-#include "chrome/worker/worker_thread.h"
-
-WorkerProcess::WorkerProcess()
-  : ChildProcess(new WorkerThread()) {
-}
-
-WorkerProcess::~WorkerProcess() {
-}
diff --git a/chrome/worker/worker_process.h b/chrome/worker/worker_process.h
deleted file mode 100644
index da76781..0000000
--- a/chrome/worker/worker_process.h
+++ /dev/null
@@ -1,28 +0,0 @@
-// Copyright (c) 2009 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.
-
-#ifndef CHROME_WORKER_WORKER_PROCESS_H_
-#define CHROME_WORKER_WORKER_PROCESS_H_
-
-#include "chrome/common/child_process.h"
-
-// Represents the worker end of the renderer<->worker connection. The
-// opposite end is the WorkerProcessHost. This is a singleton object for
-// each worker process.
-class WorkerProcess : public ChildProcess {
- public:
-  WorkerProcess();
-  virtual ~WorkerProcess();
-
-  // Returns a pointer to the PluginProcess singleton instance.
-  static WorkerProcess* current() {
-    return static_cast<WorkerProcess*>(ChildProcess::current());
-  }
-
- private:
-
-  DISALLOW_COPY_AND_ASSIGN(WorkerProcess);
-};
-
-#endif  // CHROME_WORKER_WORKER_PROCESS_H_
diff --git a/chrome/worker/worker_thread.cc b/chrome/worker/worker_thread.cc
index 8091dbf..f37904a 100644
--- a/chrome/worker/worker_thread.cc
+++ b/chrome/worker/worker_thread.cc
@@ -6,7 +6,6 @@
 
 #include "chrome/common/worker_messages.h"
 #include "chrome/worker/webworkerclient_proxy.h"
-#include "chrome/worker/worker_process.h"
 #include "chrome/worker/worker_webkitclient_impl.h"
 #include "third_party/WebKit/WebKit/chromium/public/WebKit.h"