Revert r159780 "Remove needless comments from ScriptPromise" Revert r159742 "generalize CallbacksPromiseAdapter" Revert r159698 "Decouple ScriptPromise creation from ScriptPromiseResolver." Revert r159797 "Move KeyCodeConversion test near its implementation file." Revert r159697 Reland "Move keyboard related files from core/ to platform.""

TBR=abarth

Review URL: https://codereview.chromium.org/28513002

git-svn-id: svn://svn.chromium.org/blink/trunk@159938 bbb929c8-8fbe-4397-9dbb-9b2b20218538