Reland: GC: Refactor public incremental marking interface in heap

src/heap/incremental-marking.cc

Index: src/heap/incremental-marking.cc
diff --git a/src/heap/incremental-marking.cc b/src/heap/incremental-marking.cc
index 6b447715c895843e09040e617166debcdb11b44b..106b72e3c9729feeaa1069d0e8e2723edbfb0405 100644
--- a/src/heap/incremental-marking.cc
+++ b/src/heap/incremental-marking.cc
@@ -16,22 +16,34 @@ namespace v8 {
 namespace internal {
 
 
+IncrementalMarking::StepActions IncrementalMarking::NoForcedStepActions() {
+  return StepActions(IncrementalMarking::NO_GC_VIA_STACK_GUARD,
+                     IncrementalMarking::DO_NOT_FORCE_MARKING,
+                     IncrementalMarking::DO_NOT_FORCE_COMPLETION);
+}
+
+
 IncrementalMarking::IncrementalMarking(Heap* heap)
     : heap_(heap),
       state_(STOPPED),
+      is_compacting_(false),
       steps_count_(0),
       old_generation_space_available_at_start_of_incremental_(0),
       old_generation_space_used_at_start_of_incremental_(0),
+      bytes_rescanned_(0),
       should_hurry_(false),
       marking_speed_(0),
+      bytes_scanned_(0),
       allocated_(0),
+      write_barriers_invoked_since_last_step_(0),
       idle_marking_delay_counter_(0),
       no_marking_scope_depth_(0),
       unscanned_bytes_of_large_object_(0),
       was_activated_(false),
       weak_closure_was_overapproximated_(false),
       weak_closure_approximation_rounds_(0),
-      request_type_(COMPLETE_MARKING) {}
+      request_type_(COMPLETE_MARKING),
+      gc_callback_flags_(kNoGCCallbackFlags) {}
 
 
 void IncrementalMarking::RecordWriteSlow(HeapObject* obj, Object** slot,
@@ -458,9 +470,12 @@ static void PatchIncrementalMarkingRecordWriteStubs(
 }
 
 
-void IncrementalMarking::Start(int mark_compact_flags) {
+void IncrementalMarking::Start(int mark_compact_flags,
+                               const GCCallbackFlags gc_callback_flags,
+                               const char* reason) {
   if (FLAG_trace_incremental_marking) {
-    PrintF("[IncrementalMarking] Start\n");
+    PrintF("[IncrementalMarking] Start (%s)\n",
+           (reason == nullptr) ? "unknown reason" : reason);
   }
   DCHECK(FLAG_incremental_marking);
   DCHECK(FLAG_incremental_marking_steps);
@@ -470,6 +485,7 @@ void IncrementalMarking::Start(int mark_compact_flags) {
 
   ResetStepCounters();
 
+  gc_callback_flags_ = gc_callback_flags;
   was_activated_ = true;
 
   if (!heap_->mark_compact_collector()->sweeping_in_progress()) {
@@ -812,7 +828,7 @@ void IncrementalMarking::Epilogue() {
 
 void IncrementalMarking::OldSpaceStep(intptr_t allocated) {
   if (IsStopped() && ShouldActivateEvenWithoutIdleNotification()) {
-    Start(Heap::kNoGCFlags);
+    Start(Heap::kNoGCFlags, kNoGCCallbackFlags, "old space step");
   } else {
     Step(allocated * kFastMarking / kInitialMarkingSpeed, GC_VIA_STACK_GUARD);
   }