Refactor space bitmap to support different alignments.

Required for:
Using space bitmaps instead of std::set in mod union table +
remembered set.
Using a bitmap instead of set for large object marking.

Bug: 13571028

Change-Id: Id024e9563d4ca4278f79607cdb2f81895121b113
diff --git a/compiler/image_writer.h b/compiler/image_writer.h
index 92b24f6..ee241cb 100644
--- a/compiler/image_writer.h
+++ b/compiler/image_writer.h
@@ -173,7 +173,7 @@
   const byte* oat_data_begin_;
 
   // Image bitmap which lets us know where the objects inside of the image reside.
-  UniquePtr<gc::accounting::SpaceBitmap> image_bitmap_;
+  UniquePtr<gc::accounting::ContinuousSpaceBitmap> image_bitmap_;
 
   // Offset from oat_data_begin_ to the stubs.
   uint32_t interpreter_to_interpreter_bridge_offset_;