Do not send JavaScript results if they are not needed.

If large enough, they might OOM the IPC.

BUG=971688,972409

(cherry picked from commit 8e3ebe9c79594a3e0f00e5aac452f33a2ca1f2b6)

Change-Id: Icd25172270b1f111bd70b0d23c655d6d65c429d7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1651058
Commit-Queue: Avi Drissman <avi@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Avi Drissman <avi@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#667732}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1653351
Cr-Commit-Position: refs/branch-heads/3809@{#224}
Cr-Branched-From: d82dec1a818f378c464ba307ddd9c92133eac355-refs/heads/master@{#665002}

• content/browser/frame_host/render_frame_host_impl.cc[diff]
• content/common/frame.mojom[diff]
• content/renderer/render_frame_impl.cc[diff]
• content/renderer/render_frame_impl.h[diff]