Make StringImpl's content immutable

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

Index: third_party/WebKit/Source/bindings/core/v8/ScriptValueSerializer.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/ScriptValueSerializer.cpp b/third_party/WebKit/Source/bindings/core/v8/ScriptValueSerializer.cpp
index 5a4771201475d190c3aee72441442f944edba109..3bd0390146d9043f971387b6fb751005509455e8 100644
--- a/third_party/WebKit/Source/bindings/core/v8/ScriptValueSerializer.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/ScriptValueSerializer.cpp
@@ -360,9 +360,8 @@ 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)