Use new downcast helper for blink::HTMLPictureElement

This CL has two goals,
1. Use To<HTMLPictureElement> and DynamicTo<HTMLPictureElement> as new
   downcast helper
2. Use IsA<HTMLPictureElement>(element) in place of
   IsHTMLPictureElement(element)

Bug: 891908
Change-Id: I1e4a3a63e326bf9c93c0dd170907cb58f0a4722b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1846429Reviewed-by: Christian Biesinger <cbiesinger@chromium.org>
Commit-Queue: Abhijeet Kandalkar <abhijeet@igalia.com>
Cr-Commit-Position: refs/heads/master@{#703757}

third_party/blink/renderer/core/frame/frame_serializer.cc

@@ -384,7 +384,7 @@ void FrameSerializer::AddResourceForElement(Document& document,
   if (const auto* image = ToHTMLImageElementOrNull(element)) {
     AtomicString image_url_value;
     const Element* parent = element.parentElement();
-    if (parent && IsHTMLPictureElement(parent)) {
+    if (parent && IsA<HTMLPictureElement>(parent)) {
       // If parent element is <picture>, use ImageSourceURL() to get best fit
       // image URL from sibling source.
       image_url_value = image->ImageSourceURL();

third_party/blink/renderer/core/html/html_image_element.cc

@@ -328,7 +328,7 @@ ImageCandidate HTMLImageElement::FindBestFitImageFromPictureParent() {
   DCHECK(IsMainThread());
   Node* parent = parentNode();
   source_ = nullptr;
-  if (!parent || !IsHTMLPictureElement(*parent))
+  if (!parent || !IsA<HTMLPictureElement>(*parent))
     return ImageCandidate();
   for (Node* child = parent->firstChild(); child;
        child = child->nextSibling()) {
@@ -418,7 +418,7 @@ Node::InsertionNotificationRequest HTMLImageElement::InsertedInto(
   if (listener_)
     GetDocument().GetMediaQueryMatcher().AddViewportListener(listener_);
   bool was_added_to_picture_parent = false;
-  if (auto* picture_parent = ToHTMLPictureElementOrNull(parentNode())) {
+  if (auto* picture_parent = DynamicTo<HTMLPictureElement>(parentNode())) {
     picture_parent->AddListenerToSourceChildren();
     was_added_to_picture_parent = picture_parent == insertion_point;
   }
@@ -446,7 +446,7 @@ void HTMLImageElement::RemovedFrom(ContainerNode& insertion_point) {
     ResetFormOwner();
   if (listener_) {
     GetDocument().GetMediaQueryMatcher().RemoveViewportListener(listener_);
-    if (auto* picture_parent = ToHTMLPictureElementOrNull(parentNode()))
+    if (auto* picture_parent = DynamicTo<HTMLPictureElement>(parentNode()))
       picture_parent->RemoveListenerFromSourceChildren();
   }
   HTMLElement::RemovedFrom(insertion_point);

third_party/blink/renderer/core/html/html_source_element.cc

@@ -100,8 +100,13 @@ Node::InsertionNotificationRequest HTMLSourceElement::InsertedInto(
   Element* parent = parentElement();
   if (auto* media = ToHTMLMediaElementOrNull(parent))
     media->SourceWasAdded(this);
-  if (parent == insertion_point && IsHTMLPictureElement(parent))
-    ToHTMLPictureElement(parent)->SourceOrMediaChanged();
+
+  auto* html_picture_element = parent == insertion_point
+                                   ? DynamicTo<HTMLPictureElement>(parent)
+                                   : nullptr;
+  if (html_picture_element)
+    html_picture_element->SourceOrMediaChanged();
+
   return kInsertionDone;
 }
 
@@ -112,7 +117,7 @@ void HTMLSourceElement::RemovedFrom(ContainerNode& removal_root) {
     parent = DynamicTo<Element>(&removal_root);
   if (auto* media = ToHTMLMediaElementOrNull(parent))
     media->SourceWasRemoved(this);
-  if (auto* picture = ToHTMLPictureElementOrNull(parent)) {
+  if (auto* picture = DynamicTo<HTMLPictureElement>(parent)) {
     RemoveMediaQueryListListener();
     if (was_removed_from_parent)
       picture->SourceOrMediaChanged();
@@ -177,13 +182,13 @@ void HTMLSourceElement::ParseAttribute(
     CreateMediaQueryList(params.new_value);
   if (name == kSrcsetAttr || name == kSizesAttr || name == kMediaAttr ||
       name == kTypeAttr) {
-    if (auto* picture = ToHTMLPictureElementOrNull(parentElement()))
+    if (auto* picture = DynamicTo<HTMLPictureElement>(parentElement()))
       picture->SourceOrMediaChanged();
   }
 }
 
 void HTMLSourceElement::NotifyMediaQueryChanged() {
-  if (auto* picture = ToHTMLPictureElementOrNull(parentElement()))
+  if (auto* picture = DynamicTo<HTMLPictureElement>(parentElement()))
     picture->SourceOrMediaChanged();
 }
 

third_party/blink/renderer/core/inspector/inspector_css_agent.cc

@@ -264,7 +264,7 @@ bool GetColorsFromRect(PhysicalRect rect,
 
     if (IsA<HTMLCanvasElement>(element) || IsHTMLEmbedElement(element) ||
         IsHTMLImageElement(element) || IsHTMLObjectElement(element) ||
-        IsHTMLPictureElement(element) || element->IsSVGElement() ||
+        IsA<HTMLPictureElement>(element) || element->IsSVGElement() ||
         IsHTMLVideoElement(element)) {
       colors.clear();
       found_opaque_color = false;

third_party/blink/renderer/core/loader/image_loader.cc

@@ -486,7 +486,7 @@ void ImageLoader::DoUpdateFromElement(
     resource_request.SetReferrerPolicy(referrer_policy);
 
     // Correct the RequestContext if necessary.
-    if (IsHTMLPictureElement(GetElement()->parentNode()) ||
+    if (IsA<HTMLPictureElement>(GetElement()->parentNode()) ||
         !GetElement()->FastGetAttribute(html_names::kSrcsetAttr).IsNull()) {
       resource_request.SetRequestContext(mojom::RequestContextType::IMAGE_SET);
     } else if (IsHTMLObjectElement(GetElement())) {