Make unittests work in component build

src/heap/gc-tracer.h

 // Copyright 2014 the V8 project 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 V8_HEAP_GC_TRACER_H_
 #define V8_HEAP_GC_TRACER_H_
 
 #include "src/base/compiler-specific.h"
 #include "src/base/platform/platform.h"
 #include "src/base/ring-buffer.h"
@@ skipping 77 matching lines @@
   F(SCAVENGER_WEAK)
 
 #define TRACE_GC(tracer, scope_id)                             \
   GCTracer::Scope::ScopeId gc_tracer_scope_id(scope_id);       \
   GCTracer::Scope gc_tracer_scope(tracer, gc_tracer_scope_id); \
   TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8.gc"),             \
                GCTracer::Scope::Name(gc_tracer_scope_id))
 
 // GCTracer collects and prints ONE line after each garbage collector
 // invocation IFF --trace_gc is used.
-class GCTracer {
+class V8_EXPORT_PRIVATE GCTracer {
  public:
   struct IncrementalMarkingInfos {
     IncrementalMarkingInfos() : duration(0), longest_step(0), steps(0) {}
 
     void Update(double duration) {
       steps++;
       this->duration += duration;
       if (duration > longest_step) {
         longest_step = duration;
       }
@@ skipping 316 matching lines @@
   base::RingBuffer<BytesAndDuration> recorded_old_generation_allocations_;
   base::RingBuffer<double> recorded_context_disposal_times_;
   base::RingBuffer<double> recorded_survival_ratios_;
 
   DISALLOW_COPY_AND_ASSIGN(GCTracer);
 };
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_HEAP_GC_TRACER_H_