[heap] Fix semaphore flaky crasher in ScavengerCollector.

Bug: v8:8228
Change-Id: I5a666d3bfebe4bce9e06cc6a7fd82aac1fbf2a61
Reviewed-on: https://chromium-review.googlesource.com/1249144Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Hannes Payer <hpayer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#56269}

src/heap/heap.cc

@@ -1925,8 +1925,7 @@ void Heap::Scavenge() {
   // Implements Cheney's copying algorithm
   LOG(isolate_, ResourceEvent("scavenge", "begin"));
 
-  ScavengerCollector scavenger_collector(this);
-  scavenger_collector.CollectGarbage();
+  scavenger_collector_->CollectGarbage();
 
   LOG(isolate_, ResourceEvent("scavenge", "end"));
 
@@ -4348,6 +4347,9 @@ void Heap::SetUp() {
   heap_controller_ = new HeapController(this);
 
   mark_compact_collector_ = new MarkCompactCollector(this);
+
+  scavenger_collector_ = new ScavengerCollector(this);
+
   incremental_marking_ =
       new IncrementalMarking(this, mark_compact_collector_->marking_worklist(),
                              mark_compact_collector_->weak_objects());
@@ -4609,6 +4611,11 @@ void Heap::TearDown() {
   }
 #endif  // ENABLE_MINOR_MC
 
+  if (scavenger_collector_ != nullptr) {
+    delete scavenger_collector_;
+    scavenger_collector_ = nullptr;
+  }
+
   if (array_buffer_collector_ != nullptr) {
     delete array_buffer_collector_;
     array_buffer_collector_ = nullptr;

src/heap/heap.h

@@ -196,6 +196,7 @@ class PagedSpace;
 class RootVisitor;
 class ScavengeJob;
 class Scavenger;
+class ScavengerCollector;
 class Space;
 class StoreBuffer;
 class StressScavengeObserver;
@@ -2102,6 +2103,7 @@ class Heap {
   GCTracer* tracer_ = nullptr;
   MarkCompactCollector* mark_compact_collector_ = nullptr;
   MinorMarkCompactCollector* minor_mark_compact_collector_ = nullptr;
+  ScavengerCollector* scavenger_collector_ = nullptr;
   ArrayBufferCollector* array_buffer_collector_ = nullptr;
   MemoryAllocator* memory_allocator_ = nullptr;
   StoreBuffer* store_buffer_ = nullptr;