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/jni_internal.h b/src/jni_internal.h
index 95bc281..606887c 100644
--- a/src/jni_internal.h
+++ b/src/jni_internal.h
@@ -19,9 +19,9 @@
 
 #include "jni.h"
 
+#include "base/macros.h"
 #include "heap.h"
 #include "indirect_reference_table.h"
-#include "macros.h"
 #include "mutex.h"
 #include "reference_table.h"
 #include "runtime.h"