A sizes attribute parser

Source/core/html/HTMLImageElement.cpp

Index: Source/core/html/HTMLImageElement.cpp
diff --git a/Source/core/html/HTMLImageElement.cpp b/Source/core/html/HTMLImageElement.cpp
index 398e78e63dd32c4cae4e7b5d529cc97d90653f20..3ee95ca248673f595dbf653ca55f25e108092de3 100644
--- a/Source/core/html/HTMLImageElement.cpp
+++ b/Source/core/html/HTMLImageElement.cpp
@@ -27,6 +27,7 @@
 #include "HTMLNames.h"
 #include "RuntimeEnabledFeatures.h"
 #include "bindings/v8/ScriptEventListener.h"
+#include "core/css/parser/SizesAttributeParser.h"
 #include "core/dom/Attribute.h"
 #include "core/fetch/ImageResource.h"
 #include "core/html/HTMLAnchorElement.h"
@@ -49,6 +50,7 @@ HTMLImageElement::HTMLImageElement(Document& document, HTMLFormElement* form)
     , m_compositeOperator(CompositeSourceOver)
     , m_imageDevicePixelRatio(1.0f)
     , m_formWasSetByParser(false)
+    , m_effectiveSize(0)
 {
     ScriptWrappable::init(this);
     if (form && form->inDocument()) {
@@ -165,6 +167,8 @@ void HTMLImageElement::parseAttribute(const QualifiedName& name, const AtomicStr
                 toRenderImage(renderer())->setImageDevicePixelRatio(m_imageDevicePixelRatio);
         }
         m_imageLoader.updateFromElementIgnoringPreviousError();
+    } else if (RuntimeEnabledFeatures::pictureSizesEnabled() && name == sizesAttr) {
+        m_effectiveSize = SizesAttributeParser::findEffectiveSize(value, MediaValues::create(document(), MediaValues::DynamicMode));
     } else if (name == usemapAttr) {
         setIsLink(!value.isNull());
     } else if (name == compositeAttr) {