Enable srcset support in HTMLImageElement

Source/core/html/parser/HTMLSrcsetParser.h

Index: Source/core/html/parser/HTMLSrcsetParser.h
diff --git a/Source/core/html/parser/HTMLSrcsetParser.h b/Source/core/html/parser/HTMLSrcsetParser.h
new file mode 100644
index 0000000000000000000000000000000000000000..5a8ed98b9aadef2c10a52940543ff244903abc05
--- /dev/null
+++ b/Source/core/html/parser/HTMLSrcsetParser.h
@@ -0,0 +1,61 @@
+// Copyright 2013 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.

[abarth-chromium, 2013/09/19 18:09:52]

This isn't the correct license block.  Please use the license block described in
the style guide:

http://dev.chromium.org/blink/coding-style#TOC-License

+
+#ifndef HTMLSrcsetParser_h
+#define HTMLSrcsetParser_h
+
+#include "wtf/text/WTFString.h"
+
+namespace WebCore {
+
+class ImageCandidate {
+public:
+    ImageCandidate()

[abarth-chromium, 2013/09/19 18:09:52]

Please initialize m_scaleFactor.  Otherwise m_scaleFactor will contain
uninitalized memory.

+    {
+    }
+
+    ImageCandidate& operator=(const ImageCandidate& candidate)
+    {
+        m_string = candidate.m_string;
+        m_scaleFactor = candidate.m_scaleFactor;
+        return *this;
+    }

[abarth-chromium, 2013/09/19 18:09:52]

No need to write this code explicitly.  The compiler will insert it for you.

+
+    ImageCandidate(const String& source, unsigned start, unsigned length, float scaleFactor)
+        : m_string(source.createView(start, length))
+        , m_scaleFactor(scaleFactor)
+    {
+    }
+
+    inline String toString() const
+    {
+        if (m_string.is8Bit())
+            return String(m_string.characters8(), m_string.length());
+        return String(m_string.characters16(), m_string.length());
+    }

[abarth-chromium, 2013/09/19 18:09:52]

There's no need for the |inline| keyword here.  The compiler will insert it
automatically.

Also, m_string already has a toString() function (or something similar) that
does this work.  No need to write all this code.

[Yoav Weiss, 2013/09/20 07:31:36]

m_string is a StringView, so it doesn't have toString at the moment.
I'll add this code to StringView and only call it here.

[abarth-chromium, 2013/09/20 16:08:07]

Thanks!

+
+    inline float scaleFactor() const
+    {
+        return m_scaleFactor;
+    }
+
+    inline bool isEmpty() const
+    {
+        return m_string.isEmpty();
+    }
+
+private:
+    StringView m_string;
+    float m_scaleFactor;
+};
+
+ImageCandidate bestFitSourceForSrcsetAttribute(float deviceScaleFactor, const String& srcsetAttribute);
+
+String bestFitSourceForImageAttributes(float deviceScaleFactor, const String& srcAttribute, const String& srcsetAttribute);
+
+String bestFitSourceForImageAttributes(float deviceScaleFactor, const String& srcAttribute, ImageCandidate& srcsetImageCandidate);
+
+}
+
+#endif