Import Dart bindings as of Blink r188698. This merely copies the files over and does not attach any…

sky/engine/bindings-dart/core/dart/DartCallback.h

Index: sky/engine/bindings-dart/core/dart/DartCallback.h
diff --git a/sky/engine/platform/fonts/FontPlatformFeatures.h b/sky/engine/bindings-dart/core/dart/DartCallback.h
similarity index 77%
copy from sky/engine/platform/fonts/FontPlatformFeatures.h
copy to sky/engine/bindings-dart/core/dart/DartCallback.h
index 0585176ce1b520f704e61a939c532dd271f644fb..87e23a9da30afbfca5d0331de5032dacdb3aa884 100644
--- a/sky/engine/platform/fonts/FontPlatformFeatures.h
+++ b/sky/engine/bindings-dart/core/dart/DartCallback.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2014 Google Inc. All rights reserved.
+ * Copyright (C) 2006-2011 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
@@ -28,21 +28,27 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef SKY_ENGINE_PLATFORM_FONTS_FONTPLATFORMFEATURES_H_
-#define SKY_ENGINE_PLATFORM_FONTS_FONTPLATFORMFEATURES_H_
+#ifndef DartCallback_h
+#define DartCallback_h
 
-#include "sky/engine/platform/PlatformExport.h"
+#include "bindings/core/dart/DartIsolateDestructionObserver.h"
+
+#include <dart_api.h>
 
 namespace blink {
 
-class FontPlatformFeatures {
+class DartCallback : public DartIsolateDestructionObserver {
 public:
-    static bool canExpandAroundIdeographsInComplexText();
+    DartCallback(Dart_Handle object, Dart_Handle& exception);
+
+    ~DartCallback();
+
+    bool handleEvent(int argc, Dart_Handle* argv);
 
 private:
-    FontPlatformFeatures();
+    Dart_PersistentHandle m_callback;
 };
 
-} // namespace blink
+}
 
-#endif  // SKY_ENGINE_PLATFORM_FONTS_FONTPLATFORMFEATURES_H_
+#endif // DartCallback_h