Model each Dart library as its own ScriptState when devtools are enabled.

Source/bindings/dart/DartHandleProxy.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 31 matching lines @@
 
 class Node;
 class DartScriptValue;
 
 class DartHandleProxy {
 public:
     static v8::Handle<v8::Value> create(Dart_Handle value);
     static v8::Handle<v8::Value> createTypeProxy(Dart_Handle value, bool showStatics);
     static v8::Handle<v8::Value> createLibraryProxy(Dart_Handle value, int32_t libraryId, Dart_Handle prefix);
     static v8::Handle<v8::Value> createLocalScopeProxy(Dart_Handle localVariables);
+    static v8::Handle<v8::Value> evaluate(Dart_Handle target, Dart_Handle expression, Dart_Handle localVariables);
 
     static bool isDartProxy(v8::Handle<v8::Value>);
     static const char* getJavaScriptType(v8::Handle<v8::Value>);
     static Node* toNativeNode(v8::Handle<v8::Value>);
     static Dart_Handle unwrapValue(v8::Handle<v8::Value>);
 
 };
 
 /**
  * Helper class to manage all scopes that must be entered to safely invoke Dart
  * code.
  */
 class DartScopes {
 private:
     DartScriptValue* scriptValue;
     DartIsolateScope scope;
     DartApiScope apiScope;
     Dart_ExceptionPauseInfo previousPauseInfo;
+    bool disableBreak;
 
 public:
     Dart_PersistentHandle handle;
 
-    DartScopes(v8::Local<v8::Object> v8Handle);
+    DartScopes(v8::Local<v8::Object> v8Handle, bool disableBreak = false);
     ~DartScopes();
 };
 
 }
 
 #endif // DartHandleProxy_h