[FCP++] Image: change IsImage to IsLayoutImage

The ImagePaintTimingDetector is now using IsImage to tell whether an
object is a layout image. But this is incorrect. We shuld use
IsLayoutImage instead.

Bug: 869924
Change-Id: I018118d41cb9a434d6c13c0920ca5a1486827216
Reviewed-on: https://chromium-review.googlesource.com/c/1471219Reviewed-by: Steve Kobes <skobes@chromium.org>
Commit-Queue: Liquan (Max) Gu <maxlg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632022}

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

@@ -26,7 +26,7 @@ namespace blink {
 namespace {
 #ifndef NDEBUG
 String GetImageUrl(const LayoutObject& object) {
-  if (object.IsImage()) {
+  if (object.IsLayoutImage()) {
     const ImageResourceContent* cached_image =
         ToLayoutImage(&object)->CachedImage();
     return cached_image ? cached_image->Url().StrippedForUseAsReferrer() : "";
@@ -76,7 +76,7 @@ bool AttachedBackgroundImagesAllLoaded(const LayoutObject& object) {
 }
 
 bool IsLoaded(const LayoutObject& object) {
-  if (object.IsImage()) {
+  if (object.IsLayoutImage()) {
     const ImageResourceContent* cached_image =
         ToLayoutImage(&object)->CachedImage();
     return cached_image ? cached_image->IsLoaded() : false;

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

@@ -38,7 +38,7 @@ void PaintTimingDetector::NotifyObjectPrePaint(
   if (object.IsText()) {
     text_paint_timing_detector_->RecordText(object, painting_layer);
   }
-  if (object.IsImage() || object.IsVideo() || object.IsSVGImage() ||
+  if (object.IsLayoutImage() || object.IsVideo() || object.IsSVGImage() ||
       ImagePaintTimingDetector::HasContentfulBackgroundImage(object)) {
     image_paint_timing_detector_->RecordImage(object, painting_layer);
   }