Move EmbedderHeapTracer::TracePrologue call to the beginning of full gc

src/heap/incremental-marking.cc

 // Copyright 2012 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.
 
 #include "src/heap/incremental-marking.h"
 
 #include "src/code-stubs.h"
 #include "src/compilation-cache.h"
 #include "src/conversions.h"
 #include "src/heap/gc-idle-time-handler.h"
@@ skipping 524 matching lines @@
   if (FLAG_trace_incremental_marking) {
     PrintF("[IncrementalMarking] Start marking\n");
   }
 
   is_compacting_ = !FLAG_never_compact &&
                    heap_->mark_compact_collector()->StartCompaction(
                        MarkCompactCollector::INCREMENTAL_COMPACTION);
 
   state_ = MARKING;
 
+  if (heap_->UsingEmbedderHeapTracer()) {
+    heap_->mark_compact_collector()->embedder_heap_tracer()->TracePrologue();
+  }
+
   RecordWriteStub::Mode mode = is_compacting_
                                    ? RecordWriteStub::INCREMENTAL_COMPACTION
                                    : RecordWriteStub::INCREMENTAL;
 
   PatchIncrementalMarkingRecordWriteStubs(heap_, mode);
 
   heap_->mark_compact_collector()->EnsureMarkingDequeIsCommittedAndInitialize(
       MarkCompactCollector::kMaxMarkingDequeSize);
 
   ActivateIncrementalWriteBarrier();
@@ skipping 695 matching lines @@
 void IncrementalMarking::IncrementIdleMarkingDelayCounter() {
   idle_marking_delay_counter_++;
 }
 
 
 void IncrementalMarking::ClearIdleMarkingDelayCounter() {
   idle_marking_delay_counter_ = 0;
 }
 }  // namespace internal
 }  // namespace v8