Simplify and clean up StringTypeAdaptor and StringAppend.

third_party/WebKit/Source/wtf/text/StringOperators.h

Index: third_party/WebKit/Source/wtf/text/StringOperators.h
diff --git a/third_party/WebKit/Source/wtf/text/StringOperators.h b/third_party/WebKit/Source/wtf/text/StringOperators.h
index 9100cdaad788a75289554b3585206854c3a3b70e..fe01a2aea87a30b421de21149784645fc8017e17 100644
--- a/third_party/WebKit/Source/wtf/text/StringOperators.h
+++ b/third_party/WebKit/Source/wtf/text/StringOperators.h
@@ -31,97 +31,56 @@ template<typename StringType1, typename StringType2>
 class StringAppend final {
     STACK_ALLOCATED();
 public:
-    StringAppend(StringType1 string1, StringType2 string2);
+    StringAppend(const StringType1& string1, const StringType2& string2)
+        : m_adapter1(string1)
+        , m_adapter2(string2) {}
 
-    operator String() const;
-
-    operator AtomicString() const;
-
-    bool is8Bit();
-
-    void writeTo(LChar* destination);
+    operator String() const
+    {
+        return String(makeString(m_adapter1, m_adapter2));
+    }
+    operator AtomicString() const
+    {
+        return AtomicString(makeString(m_adapter1, m_adapter2));
+    }
 
-    void writeTo(UChar* destination);
+    unsigned length() const { return m_adapter1.length() + m_adapter2.length(); }
+    bool is8Bit() const { return m_adapter1.is8Bit() && m_adapter2.is8Bit(); }
 
-    unsigned length();
+    void writeTo(LChar* destination) const
+    {
+        DCHECK(is8Bit());
+        m_adapter1.writeTo(destination);
+        m_adapter2.writeTo(destination + m_adapter1.length());
+    }
+    void writeTo(UChar* destination) const
+    {
+        m_adapter1.writeTo(destination);
+        m_adapter2.writeTo(destination + m_adapter1.length());
+    }
 
 private:
-    StringType1 m_string1;
-    StringType2 m_string2;
+    StringTypeAdapter<StringType1> m_adapter1;
+    StringTypeAdapter<StringType2> m_adapter2;
 };
 
 template<typename StringType1, typename StringType2>
-StringAppend<StringType1, StringType2>::StringAppend(StringType1 string1, StringType2 string2)
-    : m_string1(string1)
-    , m_string2(string2)
-{
-}
-
-template<typename StringType1, typename StringType2>
-StringAppend<StringType1, StringType2>::operator String() const
-{
-    return String(makeString(m_string1, m_string2));
-}
-
-template<typename StringType1, typename StringType2>
-StringAppend<StringType1, StringType2>::operator AtomicString() const
-{
-    return AtomicString(makeString(m_string1, m_string2));
-}
-
-template<typename StringType1, typename StringType2>
-bool StringAppend<StringType1, StringType2>::is8Bit()
-{
-    StringTypeAdapter<StringType1> adapter1(m_string1);
-    StringTypeAdapter<StringType2> adapter2(m_string2);
-    return adapter1.is8Bit() && adapter2.is8Bit();
-}
-
-template<typename StringType1, typename StringType2>
-void StringAppend<StringType1, StringType2>::writeTo(LChar* destination)
-{
-    ASSERT(is8Bit());
-    StringTypeAdapter<StringType1> adapter1(m_string1);
-    StringTypeAdapter<StringType2> adapter2(m_string2);
-    adapter1.writeTo(destination);
-    adapter2.writeTo(destination + adapter1.length());
-}
-
-template<typename StringType1, typename StringType2>
-void StringAppend<StringType1, StringType2>::writeTo(UChar* destination)
-{
-    StringTypeAdapter<StringType1> adapter1(m_string1);
-    StringTypeAdapter<StringType2> adapter2(m_string2);
-    adapter1.writeTo(destination);
-    adapter2.writeTo(destination + adapter1.length());
-}
-
-template<typename StringType1, typename StringType2>
-unsigned StringAppend<StringType1, StringType2>::length()
-{
-    StringTypeAdapter<StringType1> adapter1(m_string1);
-    StringTypeAdapter<StringType2> adapter2(m_string2);
-    return adapter1.length() + adapter2.length();
-}
-
-template<typename StringType1, typename StringType2>
 class StringTypeAdapter<StringAppend<StringType1, StringType2>> {
     STACK_ALLOCATED();
 public:
-    StringTypeAdapter<StringAppend<StringType1, StringType2>>(StringAppend<StringType1, StringType2>& buffer)
+    StringTypeAdapter<StringAppend<StringType1, StringType2>>(const StringAppend<StringType1, StringType2>& buffer)
         : m_buffer(buffer)
     {
     }
 
-    unsigned length() { return m_buffer.length(); }
-
-    bool is8Bit() { return m_buffer.is8Bit(); }
+    unsigned length() const { return m_buffer.length(); }
+    bool is8Bit() const { return m_buffer.is8Bit(); }
 
-    void writeTo(LChar* destination) { m_buffer.writeTo(destination); }
-    void writeTo(UChar* destination) { m_buffer.writeTo(destination); }
+    void writeTo(LChar* destination) const { m_buffer.writeTo(destination); }
+    void writeTo(UChar* destination) const { m_buffer.writeTo(destination); }
 
 private:
-    StringAppend<StringType1, StringType2>& m_buffer;
+    const StringAppend<StringType1, StringType2>& m_buffer;
 };
 
 inline StringAppend<const char*, String> operator+(const char* string1, const String& string2)