Move no_callback_scope_depth_ and cha_ from isolate -> thread

runtime/vm/thread.h

Index: runtime/vm/thread.h
diff --git a/runtime/vm/thread.h b/runtime/vm/thread.h
index a27e6730bcece9856c492c647a6acdaf7d49b6bd..210fef1c39a8066dcb9be951fad9981cbf2923f1 100644
--- a/runtime/vm/thread.h
+++ b/runtime/vm/thread.h
@@ -166,11 +166,24 @@ class Thread {
     return OFFSET_OF(Thread, isolate_);
   }
 
-  // The (topmost) CHA for the compilation in the isolate of this thread.
-  // TODO(23153): Move this out of Isolate/Thread.
+  // The (topmost) CHA for the compilation in this thread.
   CHA* cha() const;
   void set_cha(CHA* value);
 
+  int32_t no_callback_scope_depth() const {
+    return no_callback_scope_depth_;
+  }
+
+  void IncrementNoCallbackScopeDepth() {
+    ASSERT(no_callback_scope_depth_ < INT_MAX);
+    no_callback_scope_depth_ += 1;
+  }
+
+  void DecrementNoCallbackScopeDepth() {
+    ASSERT(no_callback_scope_depth_ > 0);
+    no_callback_scope_depth_ -= 1;
+  }
+
   void StoreBufferAddObject(RawObject* obj);
   void StoreBufferAddObjectGC(RawObject* obj);
 #if defined(TESTING)
@@ -445,6 +458,9 @@ LEAF_RUNTIME_ENTRY_LIST(DECLARE_MEMBERS)
 
   VMHandles reusable_handles_;
 
+  CHA* cha_;
+  int32_t no_callback_scope_depth_;
+
   // All |Thread|s are registered in the thread list.
   Thread* thread_list_next_;