Don't do work in the SharedIOBuffer constructor; use an Init method instead. ...

base/shared_memory_posix.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 "base/shared_memory.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
@@ skipping 185 matching lines @@
   file_closer.reset(fp);  // close when we go out of scope
 
   // Make sure the (new) file is the right size.
   if (size && (posix_flags & (O_RDWR | O_CREAT))) {
     // Get current size.
     struct stat stat;
     if (fstat(fileno(fp), &stat) != 0)
       return false;
     const size_t current_size = stat.st_size;
     if (current_size != size) {
-      // TODO(hawk): When finished with bug 16371, revert this CHECK() to:
-      // if (ftruncate(fileno(fp), size) != 0)
-      //   return false;
-      CHECK(!ftruncate(fileno(fp), size));
+      if (ftruncate(fileno(fp), size) != 0)
+        return false;
       if (fseeko(fp, size, SEEK_SET) != 0)
         return false;
     }
   }
 
   mapped_file_ = dup(fileno(fp));
   if (mapped_file_ == -1) {
     if (errno == EMFILE) {
       LOG(WARNING) << "Shared memory creation failed; out of file descriptors";
       return false;
@@ skipping 84 matching lines @@
 
 void SharedMemory::Unlock() {
   LockOrUnlockCommon(F_ULOCK);
 }
 
 SharedMemoryHandle SharedMemory::handle() const {
   return FileDescriptor(mapped_file_, false);
 }
 
 }  // namespace base