Let getOriginalMimeType() take a fd passed from drm java applications

This patch enables the drm framework to avoid opening files directly.
As a result, the drm framework no longer needs the sdcard read permision.

o related-to-bug: 6426185

Change-Id: Ib176c35ef4b1a1a405e8e954f19a7985266f2510
diff --git a/include/drm/DrmManagerClient.h b/include/drm/DrmManagerClient.h
index a5c6992..866edac 100644
--- a/include/drm/DrmManagerClient.h
+++ b/include/drm/DrmManagerClient.h
@@ -279,10 +279,11 @@
      * Retrieves the mime type embedded inside the original content
      *
      * @param[in] path the path of the protected content
+     * @param[in] fd the file descriptor of the protected content
      * @return String8
      *     Returns mime-type of the original content, such as "video/mpeg"
      */
-    String8 getOriginalMimeType(const String8& path);
+    String8 getOriginalMimeType(const String8& path, int fd);
 
     /**
      * Retrieves the type of the protected object (content, rights, etc..)