Switch over to the google3 unix_file File*.

I also moved macros.h to base/macros.h to ease google3 porting, at
the expense of a larger than necessary change. (I learned my lesson,
though, and didn't make the equivalent base/logging.h change.)

I'm not sure whether we want to keep the unix_file MappedFile given
our existing MemMap, but it's easier to bring it over and then remove
it (and possibly revert the removal) than to bring it over later.

Change-Id: Id50a66faa5ab17b9bc936cc9043dbc26f791f0ca
diff --git a/src/image_writer.cc b/src/image_writer.cc
index a9aa2e0..6065760 100644
--- a/src/image_writer.cc
+++ b/src/image_writer.cc
@@ -20,12 +20,12 @@
 
 #include <vector>
 
+#include "base/unix_file/fd_file.h"
 #include "class_linker.h"
 #include "class_loader.h"
 #include "compiled_method.h"
 #include "compiler.h"
 #include "dex_cache.h"
-#include "file.h"
 #include "gc/large_object_space.h"
 #include "gc/space.h"
 #include "globals.h"