[BlinkGenPropertyTrees] Fix remote frame crash UI

When a remote frame crashes, the host renderer displays a crash UI
(a sad image on a gray background) in the bounds of the crashed frame.

Previously the UI contained 2 cc layers: one for the gray background
and another for the sad image, which didn't work for
BlinkGenPropertyTrees which missed paint property update for the sad
image layer because it's not associated with a blink GraphicsLayer and
LayerTreeHost didn't know the layer so the layer was left not updated
for paint properties.

Now create one PictureLayer for the whole crash UI. This works in
BlinkGenPropertyTrees because the layer is registered as the contents
layer of the GraphicsLayer of the remote frame.

Bug: 913464
Change-Id: I4add8dfca276474141b4797239cef1f25b908dac
Reviewed-on: https://chromium-review.googlesource.com/c/1387477
Commit-Queue: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: danakj <danakj@chromium.org>
Reviewed-by: Saman Sami <samans@chromium.org>
Cr-Commit-Position: refs/heads/master@{#620519}
2 files changed