Remove "+heap" from Source/platform/DEPS.

That directory is now in Source/platform/heap/, which is already allowed.

Review URL: https://codereview.chromium.org/1346263006

git-svn-id: svn://svn.chromium.org/blink/trunk@202564 bbb929c8-8fbe-4397-9dbb-9b2b20218538
1 file changed