Revert "Remove guard flag for SK_SUPPORT_LEGACY_BACKEND_OBJECTS on flutter."

This reverts commit 333031b921264508ca1869769c1021bc08e4e07a.

Reason for revert: Flutter roll into fuchsia got reverted so now this breaks fuchsia again....

Original change's description:
> Remove guard flag for SK_SUPPORT_LEGACY_BACKEND_OBJECTS on flutter.
> 
> Bug: skia:
> Change-Id: I2c8c116f825278cae4001d169aaef42ce9a21873
> Reviewed-on: https://skia-review.googlesource.com/125725
> Commit-Queue: Greg Daniel <egdaniel@google.com>
> Reviewed-by: Brian Osman <brianosman@google.com>
> Reviewed-by: Robert Phillips <robertphillips@google.com>

TBR=egdaniel@google.com,robertphillips@google.com,brianosman@google.com

Change-Id: I78f3cfae9ba690a34372d2081e47ec793cda3392
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/127481
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
1 file changed