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

third_party/WebKit/Source/bindings/core/v8/SerializedScriptValueFactory.cpp

Index: third_party/WebKit/Source/bindings/core/v8/SerializedScriptValueFactory.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/SerializedScriptValueFactory.cpp b/third_party/WebKit/Source/bindings/core/v8/SerializedScriptValueFactory.cpp
index a1cf3967eac7c0cfaf79442f1833ee7c84e69cf8..5e2d7c5293820c4022e23d9ea46fa23569c29be2 100644
--- a/third_party/WebKit/Source/bindings/core/v8/SerializedScriptValueFactory.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/SerializedScriptValueFactory.cpp
@@ -55,20 +55,17 @@ v8::Local<v8::Value> SerializedScriptValueFactory::deserialize(
   // 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());