POSIX: Rewrite IPC's interaction with FileDescriptor

chrome/browser/renderer_host/render_widget_helper.cc

 // 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 "chrome/browser/renderer_host/render_widget_helper.h"
 
 #include "base/thread.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/renderer_host/render_process_host.h"
 #include "chrome/browser/renderer_host/resource_dispatcher_host.h"
@@ skipping 245 matching lines @@
   const std::map<TransportDIB::Id, int>::iterator
       i = allocated_dibs_.find(dib_id);
   if (i == allocated_dibs_.end())
     return NULL;
 
   base::FileDescriptor fd(dup(i->second), true);
   return TransportDIB::Map(fd);
 }
 
 void RenderWidgetHelper::AllocTransportDIB(
-    size_t size, IPC::Maybe<TransportDIB::Handle>* result) {
+    size_t size, TransportDIB::Handle* result) {
   base::SharedMemory* shared_memory = new base::SharedMemory();
   if (!shared_memory->Create(L"", false /* read write */,
                              false /* do not open existing */, size)) {
-    result->valid = false;
+    result->fd = -1;
+    result->auto_close = false;
     delete shared_memory;
     return;
   }
 
-  result->valid = true;
-  shared_memory->GiveToProcess(0 /* pid, not needed */, &result->value);
+  shared_memory->GiveToProcess(0 /* pid, not needed */, result);
 
   // Keep a copy of the file descriptor around
   AutoLock locked(allocated_dibs_lock_);
-  allocated_dibs_[shared_memory->id()] = dup(result->value.fd);
+  allocated_dibs_[shared_memory->id()] = dup(result->fd);
 }
 
 void RenderWidgetHelper::FreeTransportDIB(TransportDIB::Id dib_id) {
   AutoLock locked(allocated_dibs_lock_);
 
   const std::map<TransportDIB::Id, int>::iterator
     i = allocated_dibs_.find(dib_id);
 
   if (i != allocated_dibs_.end()) {
     close(i->second);
     allocated_dibs_.erase(i);
   } else {
     DLOG(WARNING) << "Renderer asked us to free unknown transport DIB";
   }
 }
 
 void RenderWidgetHelper::ClearAllocatedDIBs() {
   for (std::map<TransportDIB::Id, int>::iterator
        i = allocated_dibs_.begin(); i != allocated_dibs_.end(); ++i) {
     close(i->second);
   }
 
   allocated_dibs_.clear();
 }
 #endif