Android: Get rid of extra dup()s on launching child processes

content/browser/file_descriptor_info_impl.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 "content/browser/file_descriptor_info_impl.h"
 
 namespace content {
 
 // static
 scoped_ptr<FileDescriptorInfo> FileDescriptorInfoImpl::Create() {
@@ skipping 29 matching lines @@
 
 bool FileDescriptorInfoImpl::HasID(int id) const {
   for (unsigned i = 0; i < mapping_.size(); ++i) {
     if (mapping_[i].second == id)
       return true;
   }
 
   return false;
 }
 
+bool FileDescriptorInfoImpl::OwnsFD(base::PlatformFile file) const {
+  return owned_descriptors_.end() !=
+         std::find_if(
+             owned_descriptors_.begin(), owned_descriptors_.end(),
+             [file](const base::ScopedFD* fd) { return fd->get() == file; });
+}
+
+base::ScopedFD FileDescriptorInfoImpl::ReleaseFD(base::PlatformFile file) {
+  DCHECK(OwnsFD(file));
+
+  base::ScopedFD fd;
+  auto found = std::find_if(
+      owned_descriptors_.begin(), owned_descriptors_.end(),
+      [file](const base::ScopedFD* fd) { return fd->get() == file; });
+
+  (*found)->swap(fd);
+  owned_descriptors_.erase(found);
+
+  return fd.Pass();
+}
+
 void FileDescriptorInfoImpl::AddToMapping(int id, base::PlatformFile fd) {
   DCHECK(!HasID(id));
   mapping_.push_back(std::make_pair(fd, id));
 }
 
 const base::FileHandleMappingVector& FileDescriptorInfoImpl::GetMapping()
     const {
   return mapping_;
 }
 
 base::FileHandleMappingVector
 FileDescriptorInfoImpl::GetMappingWithIDAdjustment(int delta) const {
   base::FileHandleMappingVector result = mapping_;
   // Adding delta to each ID.
   for (unsigned i = 0; i < mapping_.size(); ++i)
     result[i].second += delta;
   return result;
 }
 
 }  // namespace content