API functions returning Promises should not throw exceptions.

Source/bindings/core/v8/V8Binding.h

 /*
 * Copyright (C) 2009 Google Inc. All rights reserved.
 * Copyright (C) 2012 Ericsson AB. 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.
@@ skipping 944 matching lines @@
     ~V8RethrowTryCatchScope()
     {
         // ReThrow() is a no-op if no exception has been caught, so always call.
         m_block.ReThrow();
     }
 
 private:
     v8::TryCatch& m_block;
 };
 
-class V8ResetTryCatchScope FINAL {
-public:
-    explicit V8ResetTryCatchScope(v8::TryCatch& block) : m_block(block) { }
-    ~V8ResetTryCatchScope()
-    {
-        m_block.Reset();
-    }
-
-private:
-    v8::TryCatch& m_block;
-};
-
 } // namespace blink
 
 #endif // V8Binding_h