Revert of GC plugin: improve error reporting when tracing illegal fields.

tools/clang/blink_gc_plugin/Edge.cpp

 // 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.
 
 #include "Config.h"
 #include "Edge.h"
 #include "RecordInfo.h"
 
 TracingStatus Value::NeedsTracing(NeedsTracingOption option) {
   return value_->NeedsTracing(option);
 }
 
 bool Value::NeedsFinalization() { return value_->NeedsFinalization(); }
 bool Collection::NeedsFinalization() { return info_->NeedsFinalization(); }
 
 void RecursiveEdgeVisitor::AtValue(Value*) {}
 void RecursiveEdgeVisitor::AtRawPtr(RawPtr*) {}
 void RecursiveEdgeVisitor::AtRefPtr(RefPtr*) {}
 void RecursiveEdgeVisitor::AtOwnPtr(OwnPtr*) {}
-void RecursiveEdgeVisitor::AtUniquePtr(UniquePtr*) {}
 void RecursiveEdgeVisitor::AtMember(Member*) {}
 void RecursiveEdgeVisitor::AtWeakMember(WeakMember*) {}
 void RecursiveEdgeVisitor::AtPersistent(Persistent*) {}
-void RecursiveEdgeVisitor::AtCrossThreadPersistent(CrossThreadPersistent*) {}
 void RecursiveEdgeVisitor::AtCollection(Collection*) {}
 
 void RecursiveEdgeVisitor::VisitValue(Value* e) {
   AtValue(e);
 }
 
 void RecursiveEdgeVisitor::VisitRawPtr(RawPtr* e) {
   AtRawPtr(e);
   Enter(e);
   e->ptr()->Accept(this);
   Leave();
 }
 
 void RecursiveEdgeVisitor::VisitRefPtr(RefPtr* e) {
   AtRefPtr(e);
   Enter(e);
   e->ptr()->Accept(this);
   Leave();
 }
 void RecursiveEdgeVisitor::VisitOwnPtr(OwnPtr* e) {
   AtOwnPtr(e);
   Enter(e);
   e->ptr()->Accept(this);
   Leave();
 }
 
-void RecursiveEdgeVisitor::VisitUniquePtr(UniquePtr* e) {
-  AtUniquePtr(e);
-  Enter(e);
-  e->ptr()->Accept(this);
-  Leave();
-}
-
 void RecursiveEdgeVisitor::VisitMember(Member* e) {
   AtMember(e);
   Enter(e);
   e->ptr()->Accept(this);
   Leave();
 }
 
 void RecursiveEdgeVisitor::VisitWeakMember(WeakMember* e) {
   AtWeakMember(e);
   Enter(e);
   e->ptr()->Accept(this);
   Leave();
 }
 
 void RecursiveEdgeVisitor::VisitPersistent(Persistent* e) {
   AtPersistent(e);
   Enter(e);
   e->ptr()->Accept(this);
   Leave();
 }
 
-void RecursiveEdgeVisitor::VisitCrossThreadPersistent(
-    CrossThreadPersistent* e) {
-  AtCrossThreadPersistent(e);
-  Enter(e);
-  e->ptr()->Accept(this);
-  Leave();
-}
-
 void RecursiveEdgeVisitor::VisitCollection(Collection* e) {
   AtCollection(e);
   Enter(e);
   e->AcceptMembers(this);
   Leave();
 }