Move ThreadProfiler to components/sampling_profiler

- Continues the refactoring in https://docs.google.com/document/d/12pqVqIpLb5qxmm9T9qatbVcp5UnietMcpByUc0XPfYE/edit?usp=sharing
- Callers still use ThreadProfiler to access the static methods to
  start profiling. The class is moved to a new component directory.
- Introduces a ThreadProfilerClient interface, to encapsulate //chrome
  specific details, like command-line switches.
- The concrete instance of ThreadProfilerClient is initialized at
  process startup.

NOTE: This replaces the approach started in crrev.com/c/5738563.
That chain of CLs is abandoned, although parts may be re-used later.

Bug: 354124876
Change-Id: Iffea8d4b91af0f37c05df6b4693da793bdd6cad1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5793414
Reviewed-by: Colin Blundell <blundell@chromium.org>
Reviewed-by: Mike Wittman <wittman@chromium.org>
Commit-Queue: Jason Chase <chasej@chromium.org>
Reviewed-by: Rodney Ding <rodneyding@google.com>
Cr-Commit-Position: refs/heads/main@{#1355277}