Add missing interface renaming to blink_platform.gyp

This build step was overlooked when moving platform files
from core to platform. It is causing reliable, like always,
crashes on Chrome Canary on Mac.

Going TBR because this is a release blocker. We can re-factor the gyp file later if we need to.

TBR=abarth@chromium.org
BUG=327282

Review URL: https://codereview.chromium.org/105883011

git-svn-id: svn://svn.chromium.org/blink/trunk@163565 bbb929c8-8fbe-4397-9dbb-9b2b20218538