Replace use of std container with WTF's equivalent in third_party/blink/renderer/core/content_capture/

This CL replaces the use of std::vector of std containers with
WTF::Vector and Blink::WebVector in /content_cpature.

Bug: 952716
Change-Id: I34a6539348f683d668620cdb193bfc3cbd01081d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1657870
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Changwan Ryu <changwan@chromium.org>
Reviewed-by: Tao Bai <michaelbai@chromium.org>
Commit-Queue: Miyoung Shin <myid.shin@igalia.com>
Cr-Commit-Position: refs/heads/master@{#669465}
8 files changed