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For elements with will-change:transform or directly composited images
the raster scale is not updated in response to transform scale
changes. Once the scale gets especially large, the interest rect
computed by blink starts to become less than the layer bounds.
This ends up setting a recorded_viewport_ on RasterSource that is also
less than the layer bounds. If the interest rect gets small enough, it's
possible that tiles that are in view are not completely covered by the
RasterSource. This means that we won't create tiles (much less assign
them GPU memory and schedule them) in PictureLayerTiling::CreateTile. We
did not see this with the previous implementation of directly composited
images, since the content layer never had an interest rect computed.

This change fixes this specifically for directly composited images by
always considering its raster source as covering the entire layer. This
is the definition of directly composited images (has a DrawImageRectOp
that draws into the entire layer). This allows the in view tiles to be
created, then rasterized and activated and the image no longer
disappears.

I looked into fixing the general case (see comments in the bug) but
given the regression for the images scenario and the fact that we'd like
to get a fix merged for 85, I took an approach to just fix directly
composited images.

Bug: 1110141
Change-Id: Ice3cf25508585f116edd7317718292ec9ad8a7ef
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2358888Reviewed-by: Philip Rogers <pdr@chromium.org>
Reviewed-by: vmpstr <vmpstr@chromium.org>
Commit-Queue: Daniel Libby <dlibby@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#798836}