[heap] inline allocation steps refactor

src/heap/heap.cc

Index: src/heap/heap.cc
diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index 75b7ec1fa698f824e2e82c57da0cb9947132b08f..b138ee51b83fa5c4592051fffe42ff708b2ad05a 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -52,6 +52,19 @@ struct Heap::StrongRootsList {
   StrongRootsList* next;
 };
 
+class IdleScavengeObserver : public InlineAllocationObserver {
+ public:
+  IdleScavengeObserver(Heap& heap, intptr_t step_size)
+      : InlineAllocationObserver(step_size), heap_(heap) {}
+
+  virtual void Step(int bytes_allocated) {
+    heap_.ScheduleIdleScavengeIfNeeded(bytes_allocated);
+  }
+
+ private:
+  Heap& heap_;
+};
+
 
 Heap::Heap()
     : amount_of_external_allocated_memory_(0),
@@ -129,6 +142,7 @@ Heap::Heap()
       memory_reducer_(nullptr),
       object_stats_(nullptr),
       scavenge_job_(nullptr),
+      idle_scavenge_observer_(nullptr),
       full_codegen_bytes_generated_(0),
       crankshaft_codegen_bytes_generated_(0),
       new_space_allocation_counter_(0),
@@ -4971,17 +4985,6 @@ void Heap::DisableInlineAllocation() {
 }
 
 
-void Heap::LowerInlineAllocationLimit(intptr_t step) {
-  new_space()->LowerInlineAllocationLimit(step);
-}
-
-
-void Heap::ResetInlineAllocationLimit() {
-  new_space()->LowerInlineAllocationLimit(
-      ScavengeJob::kBytesAllocatedBeforeNextIdleTask);
-}
-
-
 V8_DECLARE_ONCE(initialize_gc_once);
 
 static void InitializeGCOnce() {
@@ -5090,7 +5093,9 @@ bool Heap::SetUp() {
 
   mark_compact_collector()->SetUp();
 
-  ResetInlineAllocationLimit();
+  idle_scavenge_observer_ = new IdleScavengeObserver(
+      *this, ScavengeJob::kBytesAllocatedBeforeNextIdleTask);
+  new_space()->AddInlineAllocationObserver(idle_scavenge_observer_);
 
   return true;
 }
@@ -5189,6 +5194,10 @@ void Heap::TearDown() {
     PrintAlloctionsHash();
   }
 
+  new_space()->RemoveInlineAllocationObserver(idle_scavenge_observer_);
+  delete idle_scavenge_observer_;
+  idle_scavenge_observer_ = nullptr;
+
   delete scavenge_collector_;
   scavenge_collector_ = nullptr;