[heap] Worklist: Avoid forward decl and allow querying global pool state

Bug: chromium:738865
Change-Id: I663be62e73e9ba4e2f1aaededc6937d5ca1db179
Reviewed-on: https://chromium-review.googlesource.com/571780
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46665}

src/heap/concurrent-marking.h

@@ -7,6 +7,7 @@
 
 #include "src/allocation.h"
 #include "src/cancelable-task.h"
+#include "src/heap/worklist.h"
 #include "src/utils.h"
 #include "src/v8.h"
 
@@ -15,8 +16,6 @@ namespace internal {
 
 class Heap;
 class Isolate;
-template <typename EntryType, int SEGMENT_SIZE>
-class Worklist;
 
 class ConcurrentMarking {
  public:

src/heap/mark-compact.h

@@ -24,8 +24,6 @@ class ItemParallelJob;
 class MigrationObserver;
 class RecordMigratedSlotVisitor;
 class YoungGenerationMarkingVisitor;
-template <typename EntryType, int SEGMENT_SIZE>
-class Worklist;
 
 class ObjectMarking : public AllStatic {
  public:

src/heap/worklist.h

@@ -44,6 +44,8 @@ class Worklist {
     // thread without concurrent access.
     bool IsGlobalEmpty() { return worklist_->IsGlobalEmpty(); }
 
+    bool IsGlobalPoolEmpty() { return worklist_->IsGlobalPoolEmpty(); }
+
     size_t LocalPushSegmentSize() {
       return worklist_->LocalPushSegmentSize(task_id_);
     }