NOT FOR LANDING: Hack up CSSParser for speed.

third_party/WebKit/Source/core/css/parser/CSSTokenizerInputStream.h

 // 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.
 
 #ifndef CSSTokenizerInputStream_h
 #define CSSTokenizerInputStream_h
 
+#include "core/html/parser/InputStreamPreprocessor.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 struct CSSParserString;
 
 class CSSTokenizerInputStream {
     WTF_MAKE_NONCOPYABLE(CSSTokenizerInputStream);
-    USING_FAST_MALLOC(CSSTokenizerInputStream);
+    DISALLOW_NEW();

[esprehn, 2016/04/22 23:30:58]

always on the stack or a member :)

 public:
-    CSSTokenizerInputStream(String input);
+    explicit CSSTokenizerInputStream(const String& input)
+        : m_offset(0)
+        , m_string(input.impl())
+    {
+    }
 
-    UChar peek(unsigned);
-    inline UChar nextInputChar()

[esprehn, 2016/04/22 23:30:58]

missing const on both, also don't need inline in the class body

+    UChar peek(unsigned) const;
+    UChar nextInputChar() const
     {
         return peek(0);
     }
 
     // For fast-path code, don't replace nulls with replacement characters
-    UChar peekWithoutReplacement(unsigned lookaheadOffset)
+    UChar peekWithoutReplacement(unsigned lookaheadOffset) const
     {
-        ASSERT((m_offset + lookaheadOffset) <= m_stringLength);
-        if ((m_offset + lookaheadOffset) == m_stringLength)
+        ASSERT((m_offset + lookaheadOffset) <= length());
+        if ((m_offset + lookaheadOffset) == length())
             return '\0';
         return (*m_string)[m_offset + lookaheadOffset];
     }
 
     void advance(unsigned offset = 1) { m_offset += offset; }
     void pushBack(UChar);
 
-    double getDouble(unsigned start, unsigned end);

[esprehn, 2016/04/22 23:30:58]

missing const

+    double getDouble(unsigned start, unsigned end) const;
 
     template<bool characterPredicate(UChar)>
     unsigned skipWhilePredicate(unsigned offset)
     {
-        while ((m_offset + offset) < m_stringLength && characterPredicate((*m_string)[m_offset + offset]))
+        while ((m_offset + offset) < length() && characterPredicate((*m_string)[m_offset + offset]))
             ++offset;
         return offset;
     }
 
-    unsigned offset() const { return std::min(m_offset, m_stringLength); }
+    unsigned length() const { return m_string->length(); }
+    unsigned offset() const { return std::min(m_offset, length()); }
     CSSParserString rangeAsCSSParserString(unsigned start, unsigned length) const;
 
 private:
-    size_t m_offset;
-    const size_t m_stringLength;

[esprehn, 2016/04/22 23:30:58]

There's no reason to store the length, we have it in m_string.

+    unsigned m_offset;
     const RefPtr<StringImpl> m_string;
 };
 
+inline UChar CSSTokenizerInputStream::peek(unsigned lookaheadOffset) const
+{
+    if ((m_offset + lookaheadOffset) >= length())
+        return kEndOfFileMarker;
+    UChar result = (*m_string)[m_offset + lookaheadOffset];
+    return result ? result : 0xFFFD;
+}
+
+inline void CSSTokenizerInputStream::pushBack(UChar cc)
+{
+    --m_offset;
+    ASSERT(nextInputChar() == cc);
+}
+
 } // namespace blink
 
 #endif // CSSTokenizerInputStream_h