Fix up content URI for different users

Currently Commit Content API work only when the content URI provided by
the IME is accessible to the target application.  This is non-trivial if
the target application is running as a different user (profile) and it
is actually a possible scenario when managed profile is enabled.

This CL takes care of such a situation, by fixing up the content URI
when and only when InputContentInfo#getContentUri() is called from a
different user than the owner of the content URI.

This CL also makes it clear that we currently do not support content
URIs that already have embedded user IDs.  Since
IActivityManager#grantUriPermissionFromOwner() does not support such
URIs, we should have had a special handling for such a case, which will
be addressed in a subsequent CL.

Bug: 32427307
Bug: 32778718
Test: Made sure that Commit Content API works as expected on a managed
      profile created by
      https://github.com/googlesamples/android-testdpc
Change-Id: I19d87fc19beea248f49b59ec5a5711b95bcbb466