Implement growth policy for old space using time and space signals.

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 VM_HEAP_H_
 #define VM_HEAP_H_
 
 #include "platform/assert.h"
 #include "vm/allocation.h"
 #include "vm/flags.h"
@@ skipping 82 matching lines @@
   // point.
   // The 'visitor' function should return false if the object is not found,
   // traversal through the heap space continues.
   RawInstructions* FindObjectInCodeSpace(FindObjectVisitor* visitor);
   RawInstructions* FindObjectInStubCodeSpace(FindObjectVisitor* visitor);
 
   void CollectGarbage(Space space);
   void CollectGarbage(Space space, ApiCallbacks api_callbacks);
   void CollectAllGarbage();
 
+  // Enables growth control on the page space heaps.  This should be
+  // called before any user code is executed.
+  void EnableGrowthControl();
+
   // Accessors for inlined allocation in generated code.
   uword TopAddress();
   uword EndAddress();
   static intptr_t new_space_offset() { return OFFSET_OF(Heap, new_space_); }
 
   // Initialize the heap and register it with the isolate.
   static void Init(Isolate* isolate);
 
   // Verify that all pointers in the heap point to the heap.
   bool Verify() const;
 
   // Print heap sizes.
   void PrintSizes() const;
 
  private:
   Heap();
 
   uword AllocateNew(intptr_t size);
   uword AllocateOld(intptr_t size);
   uword AllocateCode(PageSpace* space, intptr_t size);
 
   // The different spaces used for allocation.
   Scavenger* new_space_;
   PageSpace* old_space_;
   PageSpace* code_space_;
-  PageSpace* stub_code_space_;
 
   DISALLOW_COPY_AND_ASSIGN(Heap);
 };
 
 
 #if defined(DEBUG)
 class NoGCScope : public StackResource {
  public:
   NoGCScope();
   ~NoGCScope();
  private:
   DISALLOW_COPY_AND_ASSIGN(NoGCScope);
 };
 #else  // defined(DEBUG)
 class NoGCScope : public ValueObject {
  public:
   NoGCScope() {}
  private:
   DISALLOW_COPY_AND_ASSIGN(NoGCScope);
 };
 #endif  // defined(DEBUG)
 
 }  // namespace dart
 
 #endif  // VM_HEAP_H_