Move no_callback_scope_depth_ and cha_ from isolate -> thread

runtime/vm/base_isolate.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_BASE_ISOLATE_H_
 #define VM_BASE_ISOLATE_H_
 
 #include "platform/assert.h"
 #include "vm/globals.h"
 
 namespace dart {
 
 class HandleScope;
 class StackResource;
 class Thread;
 class Zone;
 
 // A BaseIsolate contains just enough functionality to allocate
 // StackResources.  This allows us to inline the StackResource
 // constructor/destructor for performance.
 class BaseIsolate {
  public:
 #if defined(DEBUG)
   void AssertCurrentThreadIsMutator() const;
 #else
   void AssertCurrentThreadIsMutator() const {}
 #endif  // DEBUG
 
-  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;
-  }
-
 #if defined(DEBUG)
   static void AssertCurrent(BaseIsolate* isolate);
 #endif
 
  protected:
   BaseIsolate()
-      : mutator_thread_(NULL),
-        no_callback_scope_depth_(0) {
+      : mutator_thread_(NULL) {
   }
 
   ~BaseIsolate() {
     // Do not delete stack resources: top_resource_ and current_zone_.
   }
 
   Thread* mutator_thread_;
-  int32_t no_callback_scope_depth_;
 
  private:
   // During migration, some deprecated interfaces will default to using the
   // mutator_thread_ (can't use accessor in Isolate due to circular deps).
   friend class StackResource;
   DISALLOW_COPY_AND_ASSIGN(BaseIsolate);
 };
 
 }  // namespace dart
 
 #endif  // VM_BASE_ISOLATE_H_