Remove #include "oat_file.h" from class_linker.h .

Refactor the OatClass and OatMethod related functions from
ClassLinker to OatFile and ArtMethod, respectively. Refactor
the remaining ClassLinker dependencies on OatFile to break
the #include dependency and reduce incremental build times.

Test: m test-art-host
Change-Id: Iebc5b9f81b48fbcf79821cc827a5d7c4a0261bf6
diff --git a/runtime/art_method.h b/runtime/art_method.h
index 7a8f479..0d0bf20 100644
--- a/runtime/art_method.h
+++ b/runtime/art_method.h
@@ -600,13 +600,17 @@
     return hotness_count_;
   }
 
-  const uint8_t* GetQuickenedInfo() REQUIRES_SHARED(Locks::mutator_lock_);
+  const uint8_t* GetQuickenedInfo(PointerSize pointer_size) REQUIRES_SHARED(Locks::mutator_lock_);
 
   // Returns the method header for the compiled code containing 'pc'. Note that runtime
   // methods will return null for this method, as they are not oat based.
   const OatQuickMethodHeader* GetOatQuickMethodHeader(uintptr_t pc)
       REQUIRES_SHARED(Locks::mutator_lock_);
 
+  // Get compiled code for the method, return null if no code exists.
+  const void* GetOatMethodQuickCode(PointerSize pointer_size)
+      REQUIRES_SHARED(Locks::mutator_lock_);
+
   // Returns whether the method has any compiled code, JIT or AOT.
   bool HasAnyCompiledCode() REQUIRES_SHARED(Locks::mutator_lock_);