Match task runner lifetime with the cache for SVGDocumentResources
The task runner was taken from the passed ResourceFetcher, but since the
the SVGResourceDocumentContent loaded from the SVGDocumentResource can
outlive the ResourceFetcher, tasks posted to the task runner would not
be delivered if the latter was destroyed. Use the default task runner
from the AgentGroupScheduler instead since that should match the
lifetime of the SVGResourceDocumentCache (i.e the Page).
Fixed: 347724924
Change-Id: I6e04c5a665a992620451d8e0a324250f70cdef7d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5639940
Reviewed-by: Philip Rogers pdr@chromium.org
Auto-Submit: Fredrik Söderquist fs@opera.com
Commit-Queue: Philip Rogers pdr@chromium.org
Cr-Commit-Position: refs/heads/main@{#1317059}