Share the zygote's fopen overrides with nacl_helper.

chrome/browser/nacl_host/nacl_browser.cc

Index: chrome/browser/nacl_host/nacl_browser.cc
diff --git a/chrome/browser/nacl_host/nacl_browser.cc b/chrome/browser/nacl_host/nacl_browser.cc
index 7e62a0a8ae2513badb611d0b17eb87feb63866ef..f399680b6790a5ecab0786c7bd48aad82fbd6695 100644
--- a/chrome/browser/nacl_host/nacl_browser.cc
+++ b/chrome/browser/nacl_host/nacl_browser.cc
@@ -22,14 +22,7 @@ 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,