Fix some camelCase.

These are the files that are mostly right but contain a few
orthographic errors.

Change-Id: I2ca1b5fad71c24f911fd55cfc91f7031af66be99
diff --git a/src/heap_bitmap.h b/src/heap_bitmap.h
index 70684b9..aaa764a 100644
--- a/src/heap_bitmap.h
+++ b/src/heap_bitmap.h
@@ -53,7 +53,7 @@
 
   typedef void ScanCallback(Object* obj, void* finger, void* arg);
 
-  typedef void SweepCallback(size_t numPtrs, Object** ptrs, void* arg);
+  typedef void SweepCallback(size_t ptr_count, Object** ptrs, void* arg);
 
   // Initialize a HeapBitmap so that it points to a bitmap large enough to cover a heap at
   // heap_begin of heap_capacity bytes, where objects are guaranteed to be kAlignment-aligned.