[heap] refactor inline allocation step code

src/heap/spaces.h

Index: src/heap/spaces.h
diff --git a/src/heap/spaces.h b/src/heap/spaces.h
index 0bc1c175a2c019020ff17a1c1d724d3fb71decbf..1ed9ce8be96a5a934e50f9e05513a62a3ff3f450 100644
--- a/src/heap/spaces.h
+++ b/src/heap/spaces.h
@@ -2737,6 +2737,15 @@ class NewSpace : public Space {
 
   bool EnsureAllocation(int size_in_bytes, AllocationAlignment alignment);
 
+  // If we are doing inline allocation in steps, this method performs the 'step'
+  // operation. Right now incremental mark is the only consumer of inline
+  // allocation steps. `top` the address just past the last byte allocated, i.e.

[Hannes Payer (out of office), 2015/09/21 07:48:10]

top is the memory address of the bump pointer at the last inline allocation
step.

[ofrobots, 2015/09/21 20:32:58]

Did you mean: "top is the memory address of the bump pointer at the last inline
allocation"? Having "step" at the end doesn't make sense to me. This was
probably a typo, but I want to make sure we are on the same .... page (heh).

+  // determines the numbers of bytes actually allocated since the last step.
+  // `new_top` is the address where that the next byte is going be allocated

[Hannes Payer (out of office), 2015/09/21 07:48:10]

address of the bump pointer

[Hannes Payer (out of office), 2015/09/21 07:48:10]

remove "that"

+  // from. `top` and `new_top` may be different when we cross a page boundary or
+  // reset the space.
+  void InlineAllocationStep(Address top, Address new_top);
+
   friend class SemiSpaceIterator;
 };