Add chrome.tabs API extension telemetry signal and processor

Define a new extension telemetry signal type for intercepting
certain chrome.tabs API invocations. Also implement a signal processor
that processes this signal type and generates an associated report. The
actual invoking of this signal processor by the extension telemetry
service will be implemented in a follow-on CL.

Bug: 1465947
Change-Id: I085adee814e0a99eb58bd7b1d34d453fbe3fc035
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4793940


Reviewed-by: Richard Chen <richche@google.com>
Commit-Queue: Anunoy Ghosh <anunoy@chromium.org>
Reviewed-by: Xinghui Lu <xinghuilu@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1187933}