Remove some PlatformFile uses from NaCl.

components/nacl/browser/nacl_browser.h

Index: components/nacl/browser/nacl_browser.h
diff --git a/components/nacl/browser/nacl_browser.h b/components/nacl/browser/nacl_browser.h
index d97add2611914ddd1253adc3b845186221bbbab5..4216733aa46e650b888d92bdb18de5c347790845 100644
--- a/components/nacl/browser/nacl_browser.h
+++ b/components/nacl/browser/nacl_browser.h
@@ -9,6 +9,7 @@
 
 #include "base/bind.h"
 #include "base/containers/mru_cache.h"
+#include "base/files/file.h"
 #include "base/files/file_util_proxy.h"
 #include "base/memory/singleton.h"
 #include "base/memory/weak_ptr.h"
@@ -24,7 +25,7 @@ namespace nacl {
 
 // Open an immutable executable file that can be mmapped.
 // This function should only be called on a thread that can perform file IO.
-base::PlatformFile OpenNaClExecutableImpl(const base::FilePath& file_path);
+base::File OpenNaClExecutableImpl(const base::FilePath& file_path);
 
 // Represents shared state for all NaClProcessHost objects in the browser.
 class NaClBrowser {