Have srcset respond to viewport changes

Source/core/dom/Document.cpp

Index: Source/core/dom/Document.cpp
diff --git a/Source/core/dom/Document.cpp b/Source/core/dom/Document.cpp
index a9db629ba87a096cbe51212a2f4bd80f661800cd..fed884f13b914fa652486f09e3e8609fed145ca8 100644
--- a/Source/core/dom/Document.cpp
+++ b/Source/core/dom/Document.cpp
@@ -115,6 +115,7 @@
 #include "core/frame/History.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
+#include "core/frame/ViewportChangeNotifier.h"
 #include "core/frame/csp/ContentSecurityPolicy.h"
 #include "core/html/DocumentNameCollection.h"
 #include "core/html/HTMLAllCollection.h"
@@ -492,6 +493,7 @@ Document::Document(const DocumentInit& initializer, DocumentClassFlags documentC
     , m_referrerPolicy(ReferrerPolicyDefault)
     , m_directionSetOnDocumentElement(false)
     , m_writingModeSetOnDocumentElement(false)
+    , m_viewportChangeNotifier(ViewportChangeNotifier::create())
     , m_writeRecursionIsTooDeep(false)
     , m_writeRecursionDepth(0)
     , m_taskRunner(MainThreadTaskRunner::create(this))
@@ -3392,6 +3394,7 @@ void Document::evaluateMediaQueryList()
 {
     if (m_mediaQueryMatcher)
         m_mediaQueryMatcher->mediaFeaturesChanged();
+    m_viewportChangeNotifier->viewportChanged();
 }
 
 void Document::notifyResizeForViewportUnits()