V8ScriptValueSerializer: Use PartitionAlloc for the buffer, and avoid copying it into a String.

third_party/WebKit/Source/bindings/core/v8/SerializedScriptValueFactory.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 "bindings/core/v8/SerializedScriptValueFactory.h"
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptValueSerializer.h"
 #include "bindings/core/v8/Transferables.h"
 #include "bindings/core/v8/serialization/V8ScriptValueDeserializer.h"
@@ skipping 37 matching lines @@
     V8ScriptValueDeserializer deserializer(ScriptState::current(isolate),
                                            value);
     deserializer.setTransferredMessagePorts(messagePorts);
     deserializer.setBlobInfoArray(blobInfo);
     return deserializer.deserialize();
   }
   // deserialize() can run arbitrary script (e.g., setters), which could result
   // in |this| being destroyed.  Holding a RefPtr ensures we are alive (along
   // with our internal data) throughout the operation.
   RefPtr<SerializedScriptValue> protect(value);
-  String& data = value->data();
-  if (!data.impl())
+  if (!value->dataLengthInBytes())
     return v8::Null(isolate);
   static_assert(sizeof(SerializedScriptValueWriter::BufferValueType) == 2,
                 "BufferValueType should be 2 bytes");
-  data.ensure16Bit();
   // FIXME: SerializedScriptValue shouldn't use String for its underlying
   // storage. Instead, it should use SharedBuffer or Vector<uint8_t>. The
   // information stored in m_data isn't even encoded in UTF-16. Instead,
   // unicode characters are encoded as UTF-8 with two code units per UChar.
-  SerializedScriptValueReader reader(
-      reinterpret_cast<const uint8_t*>(data.impl()->characters16()),
-      2 * data.length(), blobInfo, value->blobDataHandles(),
-      ScriptState::current(isolate));
+  SerializedScriptValueReader reader(value->data(), value->dataLengthInBytes(),
+                                     blobInfo, value->blobDataHandles(),
+                                     ScriptState::current(isolate));
   ScriptValueDeserializer deserializer(reader, messagePorts,
                                        value->getArrayBufferContentsArray(),
                                        value->getImageBitmapContentsArray());
 
   // deserialize() can run arbitrary script (e.g., setters), which could result
   // in |this| being destroyed.  Holding a RefPtr ensures we are alive (along
   // with our internal data) throughout the operation.
   return deserializer.deserialize();
 }
 
 }  // namespace blink