Revert 31875 to see whether it fixes reliability bot.

base/file_util_posix.cc

Index: base/file_util_posix.cc
===================================================================
--- base/file_util_posix.cc	(revision 32064)
+++ base/file_util_posix.cc	(working copy)
@@ -667,23 +667,47 @@
 // MemoryMappedFile
 
 MemoryMappedFile::MemoryMappedFile()
-    : file_(base::kInvalidPlatformFileValue),
-      data_(NULL),
+    : data_(NULL),
       length_(0) {
 }
 
+bool MemoryMappedFile::Initialize(const base::FileDescriptor& fd) {
+  if (IsValid())
+    return false;
+
+  file_ = fd;
+
+  if (!MapFileToMemoryInternal()) {
+    CloseHandles();
+    return false;
+  }
+
+  return true;
+}
+
+bool MemoryMappedFile::MapFileToMemory(const FilePath& file_name) {
+  file_ = base::FileDescriptor(open(file_name.value().c_str(), O_RDONLY), true);
+
+  if (file_.fd == -1) {
+    LOG(ERROR) << "Couldn't open " << file_name.value();
+    return false;
+  }
+
+  return MapFileToMemoryInternal();
+}
+
 bool MemoryMappedFile::MapFileToMemoryInternal() {
   struct stat file_stat;
-  if (fstat(file_, &file_stat) == base::kInvalidPlatformFileValue) {
-    LOG(ERROR) << "Couldn't fstat " << file_ << ", errno " << errno;
+  if (fstat(file_.fd, &file_stat) == -1) {
+    LOG(ERROR) << "Couldn't fstat " << file_.fd << ", errno " << errno;
     return false;
   }
   length_ = file_stat.st_size;
 
   data_ = static_cast<uint8*>(
-      mmap(NULL, length_, PROT_READ, MAP_SHARED, file_, 0));
+      mmap(NULL, length_, PROT_READ, MAP_SHARED, file_.fd, 0));
   if (data_ == MAP_FAILED)
-    LOG(ERROR) << "Couldn't mmap " << file_ << ", errno " << errno;
+    LOG(ERROR) << "Couldn't mmap " << file_.fd << ", errno " << errno;
 
   return data_ != MAP_FAILED;
 }
@@ -691,12 +715,12 @@
 void MemoryMappedFile::CloseHandles() {
   if (data_ != NULL)
     munmap(data_, length_);
-  if (file_ != base::kInvalidPlatformFileValue)
-    close(file_);
+  if (file_.auto_close && file_.fd != -1)
+    close(file_.fd);
 
   data_ = NULL;
   length_ = 0;
-  file_ = base::kInvalidPlatformFileValue;
+  file_ = base::FileDescriptor();
 }
 
 } // namespace file_util