Mark more roots.

This is most of the stuff. (Everything that currently exists, though there's
more to come.)

Change-Id: I235a21b006820a027c494374a5b52ffefed89c32
diff --git a/src/heap.h b/src/heap.h
index c3ea080..6420a2a 100644
--- a/src/heap.h
+++ b/src/heap.h
@@ -7,11 +7,11 @@
 
 #include "globals.h"
 #include "object_bitmap.h"
-#include "thread.h"
 
 namespace art {
 
 class Class;
+class Mutex;
 class Object;
 class Space;
 class HeapBitmap;
@@ -22,7 +22,7 @@
 
   static const size_t kMaximumSize = 64 * MB;
 
-  typedef void (RootVistor)(const Object* root, void* arg);
+  typedef void (RootVisitor)(const Object* root, void* arg);
 
   // Create a heap with the requested sizes. optional boot image may
   // be NULL, otherwise it is an image filename created by ImageWriter.
@@ -175,19 +175,6 @@
   DISALLOW_IMPLICIT_CONSTRUCTORS(Heap);
 };
 
-class HeapLock {
- public:
-  HeapLock(Heap* heap) : lock_(heap->GetLock()) {
-    lock_->Lock();
-  }
-  ~HeapLock() {
-    lock_->Unlock();
-  }
- private:
-  Mutex* lock_;
-  DISALLOW_COPY_AND_ASSIGN(HeapLock);
-};
-
 }  // namespace art
 
 #endif  // ART_SRC_HEAP_H_