Share the zygote's fopen overrides with nacl_helper.

chrome/browser/nacl_host/nacl_browser.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 "chrome/browser/nacl_host/nacl_browser.h"
 
 #include "base/message_loop.h"
 #include "base/metrics/histogram.h"
 #include "base/path_service.h"
 #include "base/pickle.h"
 #include "base/win/windows_version.h"
 #include "build/build_config.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_paths_internal.h"
 #include "content/public/browser/browser_thread.h"
 
 namespace {
 
 // An arbitrary delay to coalesce multiple writes to the cache.
 const int kValidationCacheCoalescingTimeMS = 6000;
 const char kValidationCacheSequenceName[] = "NaClValidationCache";
 const FilePath::CharType kValidationCacheFileName[] =
     FILE_PATH_LITERAL("nacl_validation_cache.bin");
 
-#if defined(OS_CHROMEOS)
-// TODO(ncbray) enable on ChromeOS.
-// http://code.google.com/p/chromium/issues/detail?id=131218
-const bool kValidationCacheEnabledByDefault = false;
-#else
 const bool kValidationCacheEnabledByDefault = true;
-#endif
-
 
 enum ValidationCacheStatus {
   CACHE_MISS = 0,
   CACHE_HIT,
   CACHE_MAX
 };
 
 // Determine the name of the IRT file based on the architecture.
 #define NACL_IRT_FILE_NAME(arch_string) \
   (FILE_PATH_LITERAL("nacl_irt_")       \
@@ skipping 352 matching lines @@
     // because it can degrade the responsiveness of the browser.
     // The task is sequenced so that multiple writes happen in order.
     content::BrowserThread::PostBlockingPoolSequencedTask(
         kValidationCacheSequenceName,
         FROM_HERE,
         base::Bind(WriteCache, validation_cache_file_path_,
                    base::Owned(pickle)));
   }
   validation_cache_is_modified_ = false;
 }