Roll Fuchsia SDK from b231a7051363 to 4e9dd1487caf

The AutoRoll server is located here: https://fuchsia-sdk-chromium-roll.skia.org

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

If the roll is causing failures, please contact the current sheriff, who should
be CC'd on the roll, and stop the roller if necessary.


CQ_INCLUDE_TRYBOTS=luci.chromium.try:fuchsia_arm64_cast_audio;luci.chromium.try:fuchsia_x64_cast_audio
TBR=cr-fuchsia+bot@chromium.org

Change-Id: I6034d6753b6a59b4859110c7e63427d579d8f66d
Reviewed-on: https://chromium-review.googlesource.com/1154319Reviewed-by: Fuchsia SDK Autoroller <fuchsia-sdk-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Commit-Queue: Fuchsia SDK Autoroller <fuchsia-sdk-chromium-autoroll@skia-buildbots.google.com.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#578931}

build/fuchsia/sdk.sha1

-b231a7051363fcae82dce2dce4573f54e915908d
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+4e9dd1487caf04cf64b35b361d507df5b96a0daf
\ No newline at end of file