Temporarily disable WebCrypto layout tests.

This is to enable landing a sequence of patches:

(1) Disable tests (this CL), roll blink
(2) Land chromium side (https://codereview.chromium.org/24702003/)
(3) Land blink side (https://codereview.chromium.org/24467004), and re-enable the LayoutTests

TBR=abarth
BUG=245025

Review URL: https://codereview.chromium.org/24492006

git-svn-id: svn://svn.chromium.org/blink/trunk@158389 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Devirtualize DataTransferItemList and DataTransferItem

There's no need to separate the code into non-Chromium and Chromium bits
anymore. The embedder provides the abstraction around the platform APIs
for accessing the copy and paste/drag and drop pasteboards, and Blink
can use that abstraction directly.

R=eseidel@chromium.org

Review URL: https://codereview.chromium.org/24644006

git-svn-id: svn://svn.chromium.org/blink/trunk@158390 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Implement Promise.race

Implement Promice.race static function. It is introduced in the Promises
latest draft and Promise.any is replaced with it.

BUG=295420

Review URL: https://chromiumcodereview.appspot.com/24728002

git-svn-id: svn://svn.chromium.org/blink/trunk@158391 bbb929c8-8fbe-4397-9dbb-9b2b20218538