GC plugin: consider references equal to raw pointers.

tools/clang/blink_gc_plugin/Edge.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef TOOLS_BLINK_GC_PLUGIN_EDGE_H_
 #define TOOLS_BLINK_GC_PLUGIN_EDGE_H_
 
 #include <deque>
 
 #include "TracingStatus.h"
@@ skipping 106 matching lines @@
  protected:
   PtrEdge(Edge* ptr) : ptr_(ptr) {
     assert(ptr && "EdgePtr pointer must be non-null");
   }
  private:
   Edge* ptr_;
 };
 
 class RawPtr : public PtrEdge {
  public:
-  explicit RawPtr(Edge* ptr, bool is_ptr_class)
-      : PtrEdge(ptr), is_ptr_class_(is_ptr_class) { }
+  RawPtr(Edge* ptr, bool is_ptr_class, bool is_ref_type)
+      : PtrEdge(ptr)
+      , is_ptr_class_(is_ptr_class)
+      , is_ref_type_(is_ref_type)
+  {
+      assert(!(is_ptr_class_ && is_ref_type_));
+  }
+
   bool IsRawPtr() { return true; }
   bool IsRawPtrClass() { return is_ptr_class_; }
   LivenessKind Kind() { return kWeak; }
   bool NeedsFinalization() { return false; }
   TracingStatus NeedsTracing(NeedsTracingOption) {
     return TracingStatus::Unneeded();
   }
   void Accept(EdgeVisitor* visitor) { visitor->VisitRawPtr(this); }
+
+  bool HasReferenceType() { return is_ref_type_; }
  private:
   bool is_ptr_class_;
+  bool is_ref_type_;
 };
 
 class RefPtr : public PtrEdge {
  public:
   explicit RefPtr(Edge* ptr) : PtrEdge(ptr) { }
   bool IsRefPtr() { return true; }
   LivenessKind Kind() { return kStrong; }
   bool NeedsFinalization() { return true; }
   TracingStatus NeedsTracing(NeedsTracingOption) {
     return TracingStatus::Unneeded();
@@ skipping 88 matching lines @@
   }
 
  private:
   RecordInfo* info_;
   Members members_;
   bool on_heap_;
   bool is_root_;
 };
 
 #endif  // TOOLS_BLINK_GC_PLUGIN_EDGE_H_