Add NavigationStateKeepAlive map to StoragePartition

Move the map of PolicyContainerHosts keyed by LocalFrameToken from
PolicyContainerHost to StoragePartition. This changes how
PolicyContainerHosts are accessed. Previously there was a global map of
LocalFrameTokens to PolicyContainerHosts. Now there is a map on
StoragePartition of LocalFrameTokens to NavigationStateKeepAlives, from
which the PolicyContainerHost can be accessed. If there is not a
NavigationStateKeepAlive, the PolicyContainerHost should be accessed
directly from the RenderFrameHost.

This also introduces a source SiteInstance to NavigationStateKeepAlive
to be kept alive. This also implicitly keeps the associated
SiteInstanceGroup alive.

Navigations initiated from a different StoragePartition do not inherit
origins or policies across StoragePartitions, so the PolicyContainerHost
and source SiteInstance will not be leaked across StoragePartition
boundaries (e.g. in <webview> tags).

some NavigationPolicyContainerBuilder unit tests to browser tests
PERFETTO_TESTS=`autoninja -C out/Default perfetto_diff_tests && out/Default/bin/run_perfetto_diff_tests`

Test: Enable NavigationBrowserTest that was added previously, move
Bug: 323753235
Change-Id: I8924a8f75831e3b3da2922024349632fe057bfe6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5311170
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Charlie Reis <creis@chromium.org>
Reviewed-by: Alexander Timin <altimin@chromium.org>
Commit-Queue: Sharon Yang <yangsharon@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1291412}