Make VM state tracking to be independent of logging and profiling.

src/spaces.h

Index: src/spaces.h
diff --git a/src/spaces.h b/src/spaces.h
index 850a723666e8973e73b9b01f73e4c861d477884f..1237bdf8883134f1aa40ca6d69a4e81a5c0c22f6 100644
--- a/src/spaces.h
+++ b/src/spaces.h
@@ -301,6 +301,12 @@ class Space : public Malloced {
 
   virtual int Size() = 0;
 
+#ifdef ENABLE_HEAP_PROTECTION
+  // Protect/unprotect the space by marking it read-only/writable.
+  virtual void Protect() = 0;
+  virtual void Unprotect() = 0;
+#endif
+
 #ifdef DEBUG
   virtual void Print() = 0;
 #endif
@@ -1169,6 +1175,12 @@ class SemiSpace : public Space {
   bool Commit();
   bool Uncommit();
 
+#ifdef ENABLE_HEAP_PROTECTION
+  // Protect/unprotect the space by marking it read-only/writable.
+  virtual void Protect() {}
+  virtual void Unprotect() {}
+#endif
+
 #ifdef DEBUG
   virtual void Print();
   virtual void Verify();