RFC: Add an interface for having the browser open a pnacl support file

ppapi/api/private/finish_writing_these/ppb_nacl_private.idl

Index: ppapi/api/private/finish_writing_these/ppb_nacl_private.idl
diff --git a/ppapi/api/private/finish_writing_these/ppb_nacl_private.idl b/ppapi/api/private/finish_writing_these/ppb_nacl_private.idl
index 20e883348c0ba2bc70fde332e74f40a96d271333..f2e5075509087ff2853bfacc3261b4a88970f2b1 100644
--- a/ppapi/api/private/finish_writing_these/ppb_nacl_private.idl
+++ b/ppapi/api/private/finish_writing_these/ppb_nacl_private.idl
@@ -31,4 +31,11 @@ interface PPB_NaCl_Private_0_2 {
    * code to be processed by the graphics stack.
    */
   bool Are3DInterfacesDisabled();
+
+  /* Returns a read-only file descriptor of a file rooted in the Pnacl
+   * component directory, or -1 on error.
+   * Do we want this to take a completion callback and be async, or
+   * could we make this happen on another thread?
+   */
+  int32_t GetReadonlyPnaclFd([in] str_t filename);
 };