Initial idle GC logic.

runtime/vm/heap.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef RUNTIME_VM_HEAP_H_
 #define RUNTIME_VM_HEAP_H_
 
 #include "platform/assert.h"
 #include "vm/allocation.h"
 #include "vm/flags.h"
@@ skipping 29 matching lines @@
 #endif
     kObjectIds,
     kNumWeakSelectors
   };
 
   enum GCReason {
     kNewSpace,
     kPromotion,
     kOldSpace,
     kFull,
+    kIdle,
     kGCAtAlloc,
     kGCTestCase,
   };
 
   // Pattern for unused new space and swept old space.
   static const uint8_t kZapByte = 0xf3;
 
   ~Heap();
 
   Scavenger* new_space() { return &new_space_; }
@@ skipping 37 matching lines @@
   // object is found, traversal through the heap space stops at that
   // point.
   // The 'visitor' function should return false if the object is not found,
   // traversal through the heap space continues.
   // Returns null object if nothing is found.
   RawInstructions* FindObjectInCodeSpace(FindObjectVisitor* visitor) const;
   RawObject* FindOldObject(FindObjectVisitor* visitor) const;
   RawObject* FindNewObject(FindObjectVisitor* visitor) const;
   RawObject* FindObject(FindObjectVisitor* visitor) const;
 
+  void NotifyIdle(int64_t deadline);
+
   void CollectGarbage(Space space);
   void CollectGarbage(Space space, GCReason reason);
   void CollectAllGarbage();
   bool NeedsGarbageCollection() const {
     return old_space_.NeedsGarbageCollection();
   }
 
   void WaitForSweeperTasks(Thread* thread);
 
   // Enables growth control on the page space heaps.  This should be
@@ skipping 282 matching lines @@
 // Note: During this scope, the code pages are non-executable.
 class WritableVMIsolateScope : StackResource {
  public:
   explicit WritableVMIsolateScope(Thread* thread);
   ~WritableVMIsolateScope();
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_HEAP_H_