[DevTools] Reduce API surface of String16.

third_party/WebKit/Source/platform/inspector_protocol/String16WTF.cpp

 // Copyright 2016 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 "platform/inspector_protocol/String16WTF.h"
 
 namespace blink {
 namespace protocol {
 
 String16::String16(const String16& other) : m_impl(other.m_impl) { }
 
 String16::String16(const UChar* u, unsigned length) : m_impl(u, length) { }
 
 String16::String16(const char* characters) : String16(characters, strlen(characters)) { }
 
 String16::String16(const WTF::String& other)
 {
     if (other.isNull())
         return;
-    if (!other.is8Bit()) {
-        m_impl = other;
-        return;
-    }
-
-    UChar* data;
-    const LChar* characters = other.characters8();
-    size_t length = other.length();
-    m_impl = String::createUninitialized(length, data);
-    for (size_t i = 0; i < length; ++i)
-        data[i] = characters[i];
+    m_impl = other;
+    m_impl.ensure16Bit();
 }
 
 String16::String16(const char* characters, size_t length)
 {
     UChar* data;
     m_impl = String::createUninitialized(length, data);
     for (size_t i = 0; i < length; ++i)
         data[i] = characters[i];
 }
 
-String16 String16::createUninitialized(unsigned length, UChar*& data)
-{
-    return String::createUninitialized(length, data);
-}
-
 } // namespace protocol
 } // namespace blink