GitLab

Factor out code that manipulate profile directories into its own file,
to prepare for upcoming changes to now deleting profile data work.

There are some behavior changes:

The cache directory is created on the UI thread on ProfileImpl
construction, rather than lazily when first requested. Cache directory
is likely to be requested soon after profile creation, so should not
affect performance much.

The cache directory is now empty for incognito. The return value is
never actually used for incognito profile, so this should not change
anything.

Bug: 1065585
Change-Id: I06f86235be34f1bc30247004b57cf9c3762248f0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2140038
Commit-Queue: Bo <boliu@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#757901}