Remove MediaQueryList listener from removed HTMLSourceElement.

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

Index: third_party/WebKit/Source/core/html/HTMLSourceElement.cpp
diff --git a/third_party/WebKit/Source/core/html/HTMLSourceElement.cpp b/third_party/WebKit/Source/core/html/HTMLSourceElement.cpp
index 705ba44582dfe288415cdc8c53dd5445e6b61a15..f65e834ef53fbc00b5fdca11d4ed3da34a3eb7a1 100644
--- a/third_party/WebKit/Source/core/html/HTMLSourceElement.cpp
+++ b/third_party/WebKit/Source/core/html/HTMLSourceElement.cpp
@@ -84,11 +84,10 @@ void HTMLSourceElement::createMediaQueryList(const AtomicString& media)
     if (media.isEmpty())

[cbiesinger, 2016/09/02 19:09:22]

By the way -- I'm wondering if we should still reset m_mediaQueryList and remove
the listener if this is true? Anyway -- that's unrelated to this patch.

[Yoav Weiss, 2016/09/04 04:15:52]

I think you're right and that's another bug that would trigger spurious
downloads on resize. Good catch! :)

         return;
 
-    if (m_mediaQueryList)
-        m_mediaQueryList->removeListener(m_listener);
+    removeMediaQueryListListener();
     MediaQuerySet* set = MediaQuerySet::create(media);
     m_mediaQueryList = MediaQueryList::create(&document(), &document().mediaQueryMatcher(), set);
-    m_mediaQueryList->addListener(m_listener);
+    addMediaQueryListListener();
 }
 
 void HTMLSourceElement::didMoveToNewDocument(Document& oldDocument)
@@ -115,11 +114,25 @@ void HTMLSourceElement::removedFrom(ContainerNode* removalRoot)
         parent = toElement(removalRoot);
     if (isHTMLMediaElement(parent))
         toHTMLMediaElement(parent)->sourceWasRemoved(this);
-    if (isHTMLPictureElement(parent))
+    if (isHTMLPictureElement(parent)) {
+        removeMediaQueryListListener();
         toHTMLPictureElement(parent)->sourceOrMediaChanged();
+    }
     HTMLElement::removedFrom(removalRoot);
 }
 
+void HTMLSourceElement::removeMediaQueryListListener()
+{
+    if (m_mediaQueryList)
+        m_mediaQueryList->removeListener(m_listener);
+}
+
+void HTMLSourceElement::addMediaQueryListListener()
+{
+    if (m_mediaQueryList)
+        m_mediaQueryList->addListener(m_listener);
+}
+
 void HTMLSourceElement::setSrc(const String& url)
 {
     setAttribute(srcAttr, AtomicString(url));