mac/linux: rework plugin channel file descriptor creation

chrome/plugin/plugin_channel.cc

Index: chrome/plugin/plugin_channel.cc
diff --git a/chrome/plugin/plugin_channel.cc b/chrome/plugin/plugin_channel.cc
index b9e7a52be56a7e6b656de010c782f034e16e5b03..6264af52a7bf7385d0161b03c1c201c6147d6289 100644
--- a/chrome/plugin/plugin_channel.cc
+++ b/chrome/plugin/plugin_channel.cc
@@ -18,18 +18,11 @@
 #endif
 
 PluginChannel* PluginChannel::GetPluginChannel(
-    int process_id, MessageLoop* ipc_message_loop, int channel_fd) {
+    int process_id, MessageLoop* ipc_message_loop) {
   // map renderer's process id to a (single) channel to that process
   std::string channel_name = StringPrintf(
       "%d.r%d", base::GetCurrentProcId(), process_id);
 
-#if defined(OS_POSIX)
-  // If we were provided an already-open channel, associate it with
-  // the channel name in this process's name<->socket map.
-  if (channel_fd > 0)
-    IPC::AddChannelSocket(channel_name, channel_fd);
-#endif
-
   return static_cast<PluginChannel*>(PluginChannelBase::GetChannel(
       channel_name,
       IPC::Channel::MODE_SERVER,
@@ -38,8 +31,13 @@ PluginChannel* PluginChannel::GetPluginChannel(
       false));
 }
 
-PluginChannel::PluginChannel() : renderer_handle_(0), in_send_(0),
-                                 off_the_record_(false) {
+PluginChannel::PluginChannel()
+    : renderer_handle_(0),
+#if defined(OS_POSIX)
+      renderer_fd_(-1),
+#endif
+      in_send_(0),
+      off_the_record_(false) {
   SendUnblockingOnlyDuringDispatch();
   ChildProcess::current()->AddRefProcess();
   const CommandLine* command_line = CommandLine::ForCurrentProcess();
@@ -49,6 +47,12 @@ PluginChannel::PluginChannel() : renderer_handle_(0), in_send_(0),
 PluginChannel::~PluginChannel() {
   if (renderer_handle_)
     base::CloseProcessHandle(renderer_handle_);
+#if defined(OS_POSIX)
+  // If we still have the FD, close it.
+  if (renderer_fd_ != -1) {
+    close(renderer_fd_);
+  }
+#endif
   ChildProcess::current()->ReleaseProcess();
 }
 
@@ -144,3 +148,16 @@ void PluginChannel::CleanUp() {
 
   plugin_stubs_.clear();
 }
+
+bool PluginChannel::Init(MessageLoop* ipc_message_loop, bool create_pipe_now) {
+#if defined(OS_POSIX)
+  // This gets called when the PluginChannel is initially created. At this
+  // point, create the socketpair and assign the plugin side FD to the channel
+  // name. Keep the renderer side FD as a member variable in the PluginChannel
+  // to be able to transmit it through IPC.
+  int plugin_fd;
+  IPC::SocketPair(&plugin_fd, &renderer_fd_);
+  IPC::AddChannelSocket(channel_name(), plugin_fd);
+#endif
+  return PluginChannelBase::Init(ipc_message_loop, create_pipe_now);
+}