Have srcset respond to viewport changes

Source/core/html/HTMLImageElement.h

Index: Source/core/html/HTMLImageElement.h
diff --git a/Source/core/html/HTMLImageElement.h b/Source/core/html/HTMLImageElement.h
index c5a9530318de0e8571e8af2d0540426365c39382..9d2608f98b549f9efdc2a1130d82b6b7c4f827b1 100644
--- a/Source/core/html/HTMLImageElement.h
+++ b/Source/core/html/HTMLImageElement.h
@@ -34,9 +34,12 @@ namespace blink {
 
 class HTMLFormElement;
 class ImageCandidate;
+class MediaQueryList;
 
 class HTMLImageElement FINAL : public HTMLElement, public CanvasImageSource {
 public:
+    class Listener;
+
     static PassRefPtrWillBeRawPtr<HTMLImageElement> create(Document&);
     static PassRefPtrWillBeRawPtr<HTMLImageElement> create(Document&, HTMLFormElement*, bool createdByParser);
     static PassRefPtrWillBeRawPtr<HTMLImageElement> createForJSConstructor(Document&, int width, int height);
@@ -129,6 +132,8 @@ private:
     ImageCandidate findBestFitImageFromPictureParent();
     void setBestFitURLAndDPRFromImageCandidate(const ImageCandidate&);
     HTMLImageLoader& imageLoader() const { return *m_imageLoader; }
+    void notifyViewportChanged();
+    void createMediaQueryListIfDoesNotExist();
 
     OwnPtrWillBeMember<HTMLImageLoader> m_imageLoader;
 #if ENABLE(OILPAN)
@@ -141,6 +146,11 @@ private:
     float m_imageDevicePixelRatio;
     bool m_formWasSetByParser;
     bool m_elementCreatedByParser;
+    // Intrinsic sizing is viewport dependant if the 'w' descriptor was used for the picked resource.
+    bool m_intrinsicSizingViewportDependant;
+    // Effective size is viewport dependant if the sizes attribute's effective size used v* length units.
+    bool m_effectiveSizeViewportDependant;
+    RefPtrWillBeMember<Listener> m_listener;
 };
 
 } //namespace