Rollback of previous commit -- still under review.

runtime/vm/raw_object.h

Index: runtime/vm/raw_object.h
===================================================================
--- runtime/vm/raw_object.h	(revision 11475)
+++ runtime/vm/raw_object.h	(working copy)
@@ -1123,18 +1123,10 @@
 };
 
 
-DART_EXTERN_C {
-  Dart_Handle Dart_ExternalStringGetPeer(Dart_Handle o, void**);
-  Dart_Handle Dart_ExternalStringGetPeer(Dart_Handle, void**);
-  Dart_Handle Dart_ExternalStringGetPeer(Dart_Handle, void**);
-}
-
-
 class RawExternalOneByteString : public RawString {
   RAW_HEAP_OBJECT_IMPLEMENTATION(ExternalOneByteString);
 
   ExternalStringData<uint8_t>* external_data_;
-  friend Dart_Handle Dart_ExternalStringGetPeer(Dart_Handle o, void**);
 };
 
 
@@ -1142,7 +1134,6 @@
   RAW_HEAP_OBJECT_IMPLEMENTATION(ExternalTwoByteString);
 
   ExternalStringData<uint16_t>* external_data_;
-  friend Dart_Handle Dart_ExternalStringGetPeer(Dart_Handle, void**);
 };
 
 
@@ -1150,7 +1141,6 @@
   RAW_HEAP_OBJECT_IMPLEMENTATION(ExternalFourByteString);
 
   ExternalStringData<uint32_t>* external_data_;
-  friend Dart_Handle Dart_ExternalStringGetPeer(Dart_Handle, void**);
 };