Avoid enum equality for PageTransition

No behavioral changes. This change is part of a patch series to disallow
[in]equality operator for the enum PageTransition. It's quite
error-prone unless you know what you're doing due to qualifier bits, so
let's instead migrate clients to more explicit/readable functions.

The recently introduced PageTransitionTypeIncludingQualifiersIs() is a
drop-in replacement for enum equality but common and obvious patterns
instead adopt more specific functions.

BUG=
CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:linux_site_isolation

Review-Url: https://codereview.chromium.org/2067433002
Cr-Commit-Position: refs/heads/master@{#401570}
44 files changed