remove code from (dead) SK_SUPPORT_LEGACY_PIXELREF_UNFLATTENABLE flag

BUG=

Review URL: https://codereview.chromium.org/372303002

git-svn-id: svn://svn.chromium.org/blink/trunk@177709 bbb929c8-8fbe-4397-9dbb-9b2b20218538
IDL: Rename some methods in IdlType

I'm planning to add a base class for IdlType and IdlUnionType
to reduce duplication. Before that, rename some methods of IdlType
which are labeled "FIXME: rename to ..." so that we don't add further
FIXME comments.

No behavior changes.

BUG=345503

Review URL: https://codereview.chromium.org/374263002

git-svn-id: svn://svn.chromium.org/blink/trunk@177710 bbb929c8-8fbe-4397-9dbb-9b2b20218538