- Remove heap tracing.

runtime/vm/raw_object.h

Index: runtime/vm/raw_object.h
===================================================================
--- runtime/vm/raw_object.h	(revision 21785)
+++ runtime/vm/raw_object.h	(working copy)
@@ -415,10 +415,6 @@
   friend class Heap;
   friend class HeapProfiler;
   friend class HeapProfilerRootVisitor;
-  friend class HeapTrace;
-  friend class HeapTraceDebugObjectVisitor;
-  friend class HeapTraceHandleVisitor;
-  friend class HeapTraceVisitor;
   friend class MarkingVisitor;
   friend class Object;
   friend class RawExternalTypedData;
@@ -477,7 +473,6 @@
   intptr_t token_pos_;
   uint8_t state_bits_;  // state, is_const, is_implemented.
 
-  friend class HeapTrace;
   friend class Instance;
   friend class Object;
   friend class RawInstance;
@@ -1240,8 +1235,6 @@
   RawSmi* length_;
   RawSmi* hash_;
   RawObject** to() { return reinterpret_cast<RawObject**>(&ptr()->hash_); }
-
-  friend class HeapTrace;
 };
 
 
@@ -1252,7 +1245,6 @@
   uint8_t data_[0];
 
   friend class ApiMessageReader;
-  friend class HeapTrace;
   friend class SnapshotReader;
 };
 
@@ -1263,7 +1255,6 @@
   // Variable length data follows here.
   uint16_t data_[0];
 
-  friend class HeapTrace;
   friend class SnapshotReader;
 };
 
@@ -1343,7 +1334,6 @@
 class RawImmutableArray : public RawArray {
   RAW_HEAP_OBJECT_IMPLEMENTATION(ImmutableArray);
 
-  friend class HeapTrace;
   friend class SnapshotReader;
 };