Support booting without functioning boot.oat/art patchoat.

Bug: 17000769

Change-Id: I89c26a905af12ea288742368c2c038afd57a879a
diff --git a/runtime/oat_file.h b/runtime/oat_file.h
index 8535bf4..5b24e8f 100644
--- a/runtime/oat_file.h
+++ b/runtime/oat_file.h
@@ -40,6 +40,10 @@
 
 class OatFile {
  public:
+  // Opens an oat file contained within the given elf file. This is always opened as
+  // non-executable at the moment.
+  static OatFile* OpenWithElfFile(ElfFile* elf_file, const std::string& location,
+                                  std::string* error_msg);
   // Open an oat file. Returns NULL on failure.  Requested base can
   // optionally be used to request where the file should be loaded.
   static OatFile* Open(const std::string& filename,