Use new downcast helper for blink::BitmapImage

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

Bug: 891908
Change-Id: I1534b601cfae0f99adb15355f7f1042d1c889552
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2019644Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Abhijeet Kandalkar <abhijeet@igalia.com>
Cr-Commit-Position: refs/heads/master@{#744303}

third_party/blink/renderer/core/page/drag_image.cc

@@ -109,9 +109,10 @@ std::unique_ptr<DragImage> DragImage::Create(
     return nullptr;
 
   ImageOrientation orientation;
+  auto* bitmap_image = DynamicTo<BitmapImage>(image);
   if (should_respect_image_orientation == kRespectImageOrientation &&
-      image->IsBitmapImage())
-    orientation = ToBitmapImage(image)->CurrentFrameOrientation();
+      bitmap_image)
+    orientation = bitmap_image->CurrentFrameOrientation();
 
   SkBitmap bm;
   paint_image = Image::ResizeAndOrientImage(

third_party/blink/renderer/core/paint/compositing/composited_layer_mapping.cc

@@ -1578,8 +1578,7 @@ bool CompositedLayerMapping::IsDirectlyCompositedImage() const {
     if (!cached_image->HasImage())
       return false;
 
-    Image* image = cached_image->GetImage();
-    if (!image->IsBitmapImage())
+    if (!IsA<BitmapImage>(cached_image->GetImage()))
       return false;
 
     UseCounter::Count(GetLayoutObject().GetDocument(),

third_party/blink/renderer/core/paint/paint_timing_detector.cc

@@ -25,6 +25,7 @@
 #include "third_party/blink/renderer/core/svg/graphics/svg_image.h"
 #include "third_party/blink/renderer/core/timing/dom_window_performance.h"
 #include "third_party/blink/renderer/platform/geometry/int_rect.h"
+#include "third_party/blink/renderer/platform/graphics/bitmap_image.h"
 #include "third_party/blink/renderer/platform/graphics/image.h"
 #include "third_party/blink/renderer/platform/graphics/paint/float_clip_rect.h"
 #include "third_party/blink/renderer/platform/graphics/paint/geometry_mapper.h"
@@ -52,7 +53,7 @@ bool IsBackgroundImageContentful(const LayoutObject& object,
   }
   // Generated images are excluded here, as they are likely to serve for
   // background purpose.
-  if (!image.IsBitmapImage() && !image.IsStaticBitmapImage() &&
+  if (!IsA<BitmapImage>(image) && !image.IsStaticBitmapImage() &&
       !IsA<SVGImage>(image) && !image.IsPlaceholderImage())
     return false;
   return true;

third_party/blink/renderer/platform/graphics/bitmap_image.h

@@ -38,6 +38,7 @@
 #include "third_party/blink/renderer/platform/graphics/image_animation_policy.h"
 #include "third_party/blink/renderer/platform/image-decoders/image_animation.h"
 #include "third_party/blink/renderer/platform/timer.h"
+#include "third_party/blink/renderer/platform/wtf/casting.h"
 #include "third_party/blink/renderer/platform/wtf/forward.h"
 
 #include "third_party/skia/include/core/SkRefCnt.h"
@@ -184,7 +185,10 @@ class PLATFORM_EXPORT BitmapImage final : public Image {
   PaintImage::AnimationSequenceId reset_animation_sequence_id_ = 0;
 };
 
-DEFINE_IMAGE_TYPE_CASTS(BitmapImage);
+template <>
+struct DowncastTraits<BitmapImage> {
+  static bool AllowFrom(const Image& image) { return image.IsBitmapImage(); }
+};
 
 }  // namespace blink
 

third_party/blink/renderer/platform/graphics/graphics_layer.cc

@@ -648,9 +648,10 @@ void GraphicsLayer::SetContentsToImage(
 
   ImageOrientation image_orientation = kOriginTopLeft;
   SkMatrix matrix;
-  if (paint_image && image->IsBitmapImage() &&
+  auto* bitmap_image = DynamicTo<BitmapImage>(image);
+  if (paint_image && bitmap_image &&
       respect_image_orientation == kRespectImageOrientation) {
-    image_orientation = ToBitmapImage(image)->CurrentFrameOrientation();
+    image_orientation = bitmap_image->CurrentFrameOrientation();
     image_size_ = IntSize(paint_image.width(), paint_image.height());
     if (image_orientation.UsesWidthAsHeight())
       image_size_ = image_size_.TransposedSize();

third_party/blink/renderer/platform/graphics/image.cc

@@ -338,10 +338,9 @@ SkBitmap Image::AsSkBitmapForCurrentFrame(
   if (!paint_image)
     return {};
 
-  if (respect_image_orientation == kRespectImageOrientation &&
-      IsBitmapImage()) {
-    ImageOrientation orientation =
-        ToBitmapImage(this)->CurrentFrameOrientation();
+  auto* bitmap_image = DynamicTo<BitmapImage>(this);
+  if (respect_image_orientation == kRespectImageOrientation && bitmap_image) {
+    ImageOrientation orientation = bitmap_image->CurrentFrameOrientation();
     paint_image = ResizeAndOrientImage(paint_image, orientation);
     if (!paint_image)
       return {};