Disable file operations on NACL builds.

base/metrics/persistent_memory_allocator.h

Index: base/metrics/persistent_memory_allocator.h
diff --git a/base/metrics/persistent_memory_allocator.h b/base/metrics/persistent_memory_allocator.h
index e1c85904b2168351e5d981acd9a22fe22b8218d4..f889a030bf3e576d6a55d9ed49038442ca85d360 100644
--- a/base/metrics/persistent_memory_allocator.h
+++ b/base/metrics/persistent_memory_allocator.h
@@ -385,6 +385,7 @@ class BASE_EXPORT SharedPersistentMemoryAllocator
 };
 
 
+#if !defined(OS_NACL)  // NACL doesn't support any kind of file access in build.
 // This allocator takes a memory-mapped file object and performs allocation
 // from it. The allocator takes ownership of the file object.
 class BASE_EXPORT FilePersistentMemoryAllocator
@@ -411,6 +412,7 @@ class BASE_EXPORT FilePersistentMemoryAllocator
 
   DISALLOW_COPY_AND_ASSIGN(FilePersistentMemoryAllocator);
 };
+#endif  // !defined(OS_NACL)
 
 }  // namespace base