Move CHA field back to Isolate, pending a permanent fix.

runtime/vm/thread.cc

 // Copyright (c) 2015, 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.
 
 #include "vm/thread.h"
 
 #include "vm/isolate.h"
 #include "vm/os_thread.h"
 #include "vm/profiler.h"
 #include "vm/thread_interrupter.h"
@@ skipping 69 matching lines @@
   isolate->set_vm_tag(VMTag::kIdleTagId);
   isolate->set_thread_state(NULL);
   Profiler::EndExecution(isolate);
   isolate->set_mutator_thread(NULL);
   thread->isolate_ = NULL;
   ASSERT(Isolate::Current() == NULL);
   CleanUp();
 }
 
 
+CHA* Thread::cha() const {
+  ASSERT(isolate_ != NULL);
+  return isolate_->cha_;
+}
+
+
+void Thread::set_cha(CHA* value) {
+  ASSERT(isolate_ != NULL);
+  isolate_->cha_ = value;
+}
+
 }  // namespace dart