Add framework for Dart_Terminate which will cleanup stuff on exit.

runtime/vm/isolate.cc

 // Copyright (c) 2013, 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/isolate.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/json.h"
 #include "lib/mirrors.h"
@@ skipping 662 matching lines @@
     }
 
     // Write out the coverage data if collection has been enabled.
     CodeCoverage::Write(this);
 
     // Finalize any weak persistent handles with a non-null referent.
     FinalizeWeakPersistentHandlesVisitor visitor;
     api_state()->weak_persistent_handles().VisitHandles(&visitor);
 
     CompilerStats::Print();
-    // TODO(asiva): Move this code to Dart::Cleanup when we have that method
-    // as the cleanup for Dart::InitOnce.
-    CodeObservers::DeleteAll();
     if (FLAG_trace_isolates) {
       heap()->PrintSizes();
       megamorphic_cache_table()->PrintSizes();
       Symbols::DumpStats();
       OS::Print("[-] Stopping isolate:\n"
                 "\tisolate:    %s\n", name());
     }
   }
 
   // TODO(5411455): For now just make sure there are no current isolates
@@ skipping 358 matching lines @@
   return func.raw();
 }
 
 
 void IsolateSpawnState::Cleanup() {
   SwitchIsolateScope switch_scope(isolate());
   Dart::ShutdownIsolate();
 }
 
 }  // namespace dart