[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/1471219
Reviewed-by: Steve Kobes <skobes@chromium.org>
Commit-Queue: Liquan (Max) Gu <maxlg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632022}
2 files changed