Make StringImpl's content immutable

third_party/WebKit/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 342 matching lines @@
 {
     append(DenseArrayTag);
     doWriteUint32(numProperties);
     doWriteUint32(length);
 }
 
 String SerializedScriptValueWriter::takeWireString()
 {
     static_assert(sizeof(BufferValueType) == 2, "BufferValueType should be 2 bytes");
     fillHole();
-    String data = String(m_buffer.data(), m_buffer.size());
-    data.impl()->truncateAssumingIsolated((m_position + 1) / sizeof(BufferValueType));
-    return data;
+    ASSERT((m_position + 1) / sizeof(BufferValueType) <= m_buffer.size());
+    return String(m_buffer.data(), (m_position + 1) / sizeof(BufferValueType));
 }
 
 void SerializedScriptValueWriter::writeReferenceCount(uint32_t numberOfReferences)
 {
     append(ReferenceCountTag);
     doWriteUint32(numberOfReferences);
 }
 
 void SerializedScriptValueWriter::writeGenerateFreshObject()
 {
@@ skipping 1782 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