[DIPS] Switch from SiteDataObserver to WCO::NotifyStorageAccessed().

Part of the migration to //content.  See go/dips-move

We used to need SiteDataObserver to be notified when a site accessed
storage, but a NotifyStorageAccessed() method was recently added to
WebContentsObserver. This CL migrates to it.

Also, change all uses of ContentSettingsManager::StorageType to
blink::mojom::StorageTypeAccessed, the type that NotifyStorageAccessed()
takes.

It turns out we weren't including everything we were using. When I
stopped including page_specific_content_settings.h in some of our files,
I had to add some other includes to get things to compile again.

I wasn't able to remove page_specific_content_settings.h from
dips_bounce_detector.cc because it still calls
PageSpecificContentSettings::IncrementStatefulBounceCount(). Fixing
that will require another CL (crbug.com/343631048).

Bug: 343631047
Change-Id: If72fc16a22de3941b46777f17311d026912a1971
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5585477
Commit-Queue: Ryan Tarpine <rtarpine@chromium.org>
Reviewed-by: Anton Maliev <amaliev@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1348236}