bindings: Rename ConditionalFeature to OriginTrialFeature

Files introduced in https://crrev.com/487917 are still focusing on
only origin trials. It is confusing until it introduces other
conditional features.
Beside it, this name "ConditionalFeatures" is easy to conflict with
other methods in bindings code generation.

So this CL renames them to use OriginTrial.


TBR=dpranke

Bug: 615060
Change-Id: I4ae8bd559fe3c1af09b5313a03bc009f05b79b6f
Reviewed-on: https://chromium-review.googlesource.com/770517
Commit-Queue: Hitoshi Yoshida <[email protected]>
Reviewed-by: Yuki Shiino <[email protected]>
Reviewed-by: Kentaro Hara <[email protected]>
Reviewed-by: Ian Clelland <[email protected]>
Cr-Commit-Position: refs/heads/master@{#516949}
37 files changed