Remove MediaQueryList listener from removed HTMLSourceElement.

third_party/WebKit/Source/core/html/HTMLPictureElement.cpp

Index: third_party/WebKit/Source/core/html/HTMLPictureElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLPictureElement.cpp b/third_party/WebKit/Source/core/html/HTMLPictureElement.cpp
index 4eb8f6b945adcde8bc540b071267a5b193571a76..d8df9ff8923463e19fb425c6006d0494f03af606 100644
--- a/third_party/WebKit/Source/core/html/HTMLPictureElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLPictureElement.cpp
@@ -8,6 +8,7 @@
 #include "core/dom/ElementTraversal.h"
 #include "core/frame/UseCounter.h"
 #include "core/html/HTMLImageElement.h"
+#include "core/html/HTMLSourceElement.h"
 #include "core/loader/ImageLoader.h"
 
 namespace blink {
@@ -28,6 +29,21 @@ void HTMLPictureElement::sourceOrMediaChanged()
     }
 }
 
+void HTMLPictureElement::removeListenerFromSourceChildren()
+{
+    for (HTMLSourceElement* sourceElement = Traversal<HTMLSourceElement>::firstChild(*this); sourceElement; sourceElement = Traversal<HTMLSourceElement>::nextSibling(*sourceElement)) {
+        sourceElement->removeMediaQueryListListener();
+    }
+}
+
+void HTMLPictureElement::addListenerToSourceChildren()
+{
+    for (HTMLSourceElement* sourceElement = Traversal<HTMLSourceElement>::firstChild(*this); sourceElement; sourceElement = Traversal<HTMLSourceElement>::nextSibling(*sourceElement)) {
+        sourceElement->addMediaQueryListListener();
+    }
+}
+
+
 Node::InsertionNotificationRequest HTMLPictureElement::insertedInto(ContainerNode* insertionPoint)
 {
     UseCounter::count(document(), UseCounter::Picture);