Implement ScopedFD in terms of ScopedGeneric.

base/memory/discardable_memory_allocator_android.cc

Index: base/memory/discardable_memory_allocator_android.cc
diff --git a/base/memory/discardable_memory_allocator_android.cc b/base/memory/discardable_memory_allocator_android.cc
index 97e9abd7d6eec8baa54e2d58bed24fd6d1b2c3ba..ec51f1f0f3e01d37f4e3fd6ca2fd11ae8afe7d80 100644
--- a/base/memory/discardable_memory_allocator_android.cc
+++ b/base/memory/discardable_memory_allocator_android.cc
@@ -16,6 +16,7 @@
 #include "base/basictypes.h"
 #include "base/containers/hash_tables.h"
 #include "base/file_util.h"
+#include "base/files/scoped_file.h"
 #include "base/logging.h"
 #include "base/memory/discardable_memory.h"
 #include "base/memory/scoped_vector.h"
@@ -65,14 +66,13 @@ bool CreateAshmemRegion(const char* name,
                         size_t size,
                         int* out_fd,
                         void** out_address) {
-  int fd = ashmem_create_region(name, size);
-  if (fd < 0) {
+  base::ScopedFD fd(ashmem_create_region(name, size));
+  if (!fd) {

[viettrungluu, 2014/03/08 03:06:04]

So, it occurs to me that this is extremely confusing.

I think it'd be better for ScopedNullableGeneric to have is_valid/is_invalid
methods. (Though that throws into question the name "Nullable". D'oh.)

     DLOG(ERROR) << "ashmem_create_region() failed";
     return false;
   }
-  file_util::ScopedFD fd_closer(&fd);
 
-  const int err = ashmem_set_prot_region(fd, PROT_READ | PROT_WRITE);
+  const int err = ashmem_set_prot_region(fd.get(), PROT_READ | PROT_WRITE);
   if (err < 0) {
     DLOG(ERROR) << "Error " << err << " when setting protection of ashmem";
     return false;