Turn SearchEngineLogoUtils into SearchEngineUtils.

We have an increasing need to deduplicate bits of logic related to
DSE, such as evaluation whether the currently elected DSE is Google.

This change proposes to repurpose the SearchEngineLogoUtils class to
serve larger variety of needs now that it no longer focuses on bitmap
manipulation.

---

This is a semi-automated change: `%s/EngineLogoUtils/EngineUtils`.
The change removes 3 unused variables and redundant @VisibleForTesting
annotations reported by presubmit.

Bug: 1495498
Change-Id: I1cf1b1dafab8e781f7b57ea947b14dc84a5d0146
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5034582
Reviewed-by: Theresa Sullivan <twellington@chromium.org>
Code-Coverage: findit-for-me@appspot.gserviceaccount.com <findit-for-me@appspot.gserviceaccount.com>
Commit-Queue: Tomasz Wiszkowski <ender@google.com>
Cr-Commit-Position: refs/heads/main@{#1225865}