Zoom iframe contents according to CSS zoom on iframe element
Zoom factor is set on a root LocalFrame by its corresponding
WebFrameWidget, and previously the root frame would turn around and
apply the same zoom factor to all of its descendant frames without
regard for CSS zoom values on the <iframe> element in the embedding
document. With this change, CSS zoom value on an <iframe> multiplies
the frame-level zoom factor of the embedded document.
One result of this change is that zoom factor is no longer propagated
synchronously down the frame tree: a style update is required to
propagatee zoom factor down the frame hierarchy.
Bug: chromium:329482480
Change-Id: I729d559264afe8edb4fef7bc3b18304b71581625
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5564200
Reviewed-by: Chris Bookholt bookholt@chromium.org
Reviewed-by: Philip Rogers pdr@chromium.org
Commit-Queue: Stefan Zager szager@chromium.org
Cr-Commit-Position: refs/heads/main@{#1314932}