Reland "blink/bindings: ASAN checks to ensure proper ParkableString accesses."

This is a reland of 88924f039d0b96626c33c2183bd177952b00a2a6

Added a missing DCHECK_IS_ON() check.

Original change's description:
> blink/bindings: ASAN checks to ensure proper ParkableString accesses.
>
> A ParkableString underlying string memory should not be cached.
> Following a suggestion by pasko@, add ASAN instrumentation to make sure
> this is actually the case.
>
> Bug: 877044
> Change-Id: I463ad229b118f2e629b460f1a2beed41fc54b6a7
> Reviewed-on: https://chromium-review.googlesource.com/1216422
> Reviewed-by: Egor Pasko <pasko@chromium.org>
> Reviewed-by: Kentaro Hara <haraken@chromium.org>
> Commit-Queue: Benoit L <lizeb@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#590251}

Bug: 877044
Change-Id: I777d53528037015ff3d16cd8c5ce2b649788848b
Reviewed-on: https://chromium-review.googlesource.com/1219486
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Egor Pasko <pasko@chromium.org>
Commit-Queue: Benoit L <lizeb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#590276}
1 file changed