Chunk-wise marking stack processing.

runtime/vm/store_buffer.h

Index: runtime/vm/store_buffer.h
diff --git a/runtime/vm/store_buffer.h b/runtime/vm/store_buffer.h
index b1bd387e8fb87d8d657fd0a310adf5a94528ca57..edc307d0d375db121ba93a17c81353bb98f8fb50 100644
--- a/runtime/vm/store_buffer.h
+++ b/runtime/vm/store_buffer.h
@@ -88,8 +88,9 @@ class StoreBuffer {
   // Partially filled blocks can be reused, and there is an "inifite" supply
   // of empty blocks (reused or newly allocated). In any case, the caller
   // takes ownership of the returned block.
-  StoreBufferBlock* PopBlock();
+  StoreBufferBlock* PopNonFullBlock();
   StoreBufferBlock* PopEmptyBlock();
+  StoreBufferBlock* PopNonEmptyBlock();
 
   // Pops and returns all non-empty blocks as a linked list (owned by caller).
   StoreBufferBlock* Blocks();
@@ -100,6 +101,8 @@ class StoreBuffer {
   // Check whether non-empty blocks have exceeded kMaxNonEmpty.
   bool Overflowed();
 
+  bool IsEmpty();
+
  private:
   class List {
    public: