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

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

Index: sky/engine/bindings-dart/core/dart/DartStringCache.h
diff --git a/sky/engine/platform/graphics/GraphicsContextStateSaver.h b/sky/engine/bindings-dart/core/dart/DartStringCache.h
similarity index 56%
copy from sky/engine/platform/graphics/GraphicsContextStateSaver.h
copy to sky/engine/bindings-dart/core/dart/DartStringCache.h
index 0b35abe6a07ece3552a1802cc000830e45f18cfc..3ab2b869931e4760d5a60e65d7d64cfd6a05a385 100644
--- a/sky/engine/platform/graphics/GraphicsContextStateSaver.h
+++ b/sky/engine/bindings-dart/core/dart/DartStringCache.h
@@ -1,4 +1,5 @@
-// Copyright (C) 2013 Google Inc. All rights reserved.
+// Copyright 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
@@ -26,53 +27,49 @@
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-#ifndef SKY_ENGINE_PLATFORM_GRAPHICS_GRAPHICSCONTEXTSTATESAVER_H_
-#define SKY_ENGINE_PLATFORM_GRAPHICS_GRAPHICSCONTEXTSTATESAVER_H_
+#ifndef DartStringCache_h
+#define DartStringCache_h
 
-#include "sky/engine/platform/PlatformExport.h"
-#include "sky/engine/platform/graphics/GraphicsContext.h"
+#include "wtf/HashMap.h"
+#include "wtf/RefPtr.h"
+#include "wtf/text/StringHash.h"
+#include "wtf/text/StringImpl.h"
+
+#include <dart_api.h>
 
 namespace blink {
 
-class PLATFORM_EXPORT GraphicsContextStateSaver {
-    WTF_MAKE_FAST_ALLOCATED;
+class DartStringCache {
 public:
-    GraphicsContextStateSaver(GraphicsContext& context, bool saveAndRestore = true)
-        : m_context(context)
-        , m_saveAndRestore(saveAndRestore)
-    {
-        if (m_saveAndRestore)
-            m_context.save();
-    }
+    DartStringCache();
 
-    ~GraphicsContextStateSaver()
+    Dart_WeakPersistentHandle get(StringImpl* stringImpl, bool autoDartScope = true)
     {
-        if (m_saveAndRestore)
-            m_context.restore();
-    }
+        ASSERT(stringImpl);
 
-    void save()
-    {
-        ASSERT(!m_saveAndRestore);
-        m_context.save();
-        m_saveAndRestore = true;
-    }
+        if (m_lastStringImpl.get() == stringImpl)
+            return m_lastDartString;
 
-    void restore()
-    {
-        ASSERT(m_saveAndRestore);
-        m_context.restore();
-        m_saveAndRestore = false;
+        return getSlow(stringImpl, autoDartScope);
     }
 
-    GraphicsContext* context() const { return &m_context; }
-    bool saved() const { return m_saveAndRestore; }
+    void clearWeakHandles();
+
+    // FIXME: implement clearing on GC.
 
 private:
-    GraphicsContext& m_context;
-    bool m_saveAndRestore;
+    Dart_WeakPersistentHandle getSlow(StringImpl*, bool autoDartScope);
+    static void handleFinalizer(void*, Dart_WeakPersistentHandle, void* peer);
+
+    typedef HashMap<StringImpl*, Dart_WeakPersistentHandle> StringCache;
+    StringCache m_stringCache;
+    Dart_WeakPersistentHandle m_lastDartString;
+    // Note: RefPtr is a must as we cache by StringImpl* equality, not identity
+    // hence lastStringImpl might be not a key of the cache (in sense of identity)
+    // and hence it's not refed on addition.
+    RefPtr<StringImpl> m_lastStringImpl;
 };
 
-} // namespace blink
+}
 
-#endif  // SKY_ENGINE_PLATFORM_GRAPHICS_GRAPHICSCONTEXTSTATESAVER_H_
+#endif