compositor-worker: Introduce CompositorProxy::disconnect().

Source/bindings/core/v8/ScriptValueSerializer.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "bindings/core/v8/ScriptValueSerializer.h"
 
 #include "bindings/core/v8/V8ArrayBuffer.h"
 #include "bindings/core/v8/V8ArrayBufferView.h"
 #include "bindings/core/v8/V8Blob.h"
@@ skipping 818 matching lines @@
     else
         m_writer.writeBlob(blob->uuid(), blob->type(), blob->size());
     return 0;
 }
 
 ScriptValueSerializer::StateBase* ScriptValueSerializer::writeCompositorProxy(v8::Local<v8::Value> value, ScriptValueSerializer::StateBase* next)
 {
     CompositorProxy* compositorProxy = V8CompositorProxy::toImpl(value.As<v8::Object>());
     if (!compositorProxy)
         return nullptr;
+    if (!compositorProxy->connected())
+        return handleError(DataCloneError, "A CompositorProxy object has been disconnected, and could therefore not be cloned.", next);
     m_writer.writeCompositorProxy(*compositorProxy);
     return nullptr;
 }
 
 ScriptValueSerializer::StateBase* ScriptValueSerializer::writeFile(v8::Local<v8::Value> value, ScriptValueSerializer::StateBase* next)
 {
     File* file = V8File::toImpl(value.As<v8::Object>());
     if (!file)
         return 0;
     if (file->hasBeenClosed())
@@ skipping 1075 matching lines @@
         return false;
     uint32_t objectReference = m_openCompositeReferenceStack[m_openCompositeReferenceStack.size() - 1];
     m_openCompositeReferenceStack.shrink(m_openCompositeReferenceStack.size() - 1);
     if (objectReference >= m_objectPool.size())
         return false;
     *object = m_objectPool[objectReference];
     return true;
 }
 
 } // namespace blink